redbottle

If they look under 21, then ask for ID before handing over any cash. I always check ID if they look young. Do not engage with minors, it's illegal.
Don't pay upfront, they can see the cash but handover at end. If they don't like this, send them away. 

Have any actually useful thoughts?

Haha, I wish I had had even half that much presence of mind! Part of it was that I didn’t know if he was a member of some weird gang that would come back to bother me if I pressed the issue. super unlikely, but I think this was in the back of my mind. 

Honestly, I’ve learned that Grindr is even more full of scammers. My advice is to stick with RM ( and even there, only interact well reviewed and longer time providers).

Which is why you NEVER offer to pay ANYONE for sex over text, email, phone etc. 
It's a game of *wink*wink* where you discuss sexual interests in common. Then simply agree to meet up and agree to PAY FOR THEIR TIME. Yes, no one is dumb enough to think you're inviting them to tea, but in terms of criminality, you have limited the evidence to nothing written. SPECULATING about whether or not you were INTENDING to pay for sex is not evidence enough to convict someone. 
You were certainly not the first to fall for this scam. Learn from your mistake.

I know I've been extremely stupid, but I'd still like some feedback.
So I approached someone on grindr; they asked if I was gen. I said yes. We negotiated a price of $300.
He came over, asked for the money before we began -- I gave it. He kept saying he was nervous. Then he claimed to be 17, and was this ok with me? He said his father was outside in a car. This is a state where 17 is underage for sex. He sort of suggested that he might be ok doing something if I was ok with it, but he wouldn't even sit down, because he was so "nervous."
I asked for the money back -- even offered him $100 for his trouble. He said no, and that we were free to call the police, that he had all the texts to show I was trying to pay for sex. I'm not sure he would have followed up on it. He seemed like this little hispanic kid who might have more to lose from the police than me. But I didn't want to chance it. I let him walk away with all the money.
Incredible.
 
(Edit: btw I had met another guy on grindr and the transaction worked out just fine)

I know I've been extremely stupid, but I'd still like some feedback.
So I approached someone on grindr; they asked if I was gen. I said yes. We negotiated a price of $300.
He came over, asked for the money before we began -- I gave it. He kept saying he was nervous. Then he claimed to be 17, and was this ok with me? He said his father was outside in a car. This is a state where 17 is underage for sex. He sort of suggested that he might be ok doing something if I was ok with it, but he wouldn't even sit down, because he was so "nervous."
I asked for the money back -- even offered him $100 for his trouble. He said no, and that we were free to call the police, that he had all the texts to show I was trying to pay for sex. I'm not sure he would have followed up on it. He seemed like this little hispanic kid who might have more to lose from the police than me. But I didn't want to chance it. I let him walk away with all the money.
Incredible.
 
(Edit: btw I had met another guy on grindr and the transaction worked out just fine)

Disclaimer: I have never been into younger guys.  So luckily, underage concerns do not apply to me at all.  Just brainstorming here: the next time you meet with someone who appears too young, would you consider asking him for an ID as a backhanded compliment by saying, "Oh, you look WAY younger than the age you claim, can I see your ID to confirm?  I don't want to break any laws because our texts can all be used as evidence."  If he refuses or reacts strangely, then you'd know what to do.

Some thoughtful feedback. You and many others gave it. Just being a piece of shit and stepping on someone over and over again is totally uncalled for. 

And I guess the same is true of assholes being assholes

@redbottle, we’ve all made mistakes.  I can only wish mine were only a few hundred $.  You made it clear you’re owning it, you’re learning, you’re moving on.  Good for you!

@redbottle, I am sorry you went through this situation. I have not read thoroughly the thread, so I apologize if I am repeating what other posters said, but if you are someone who has something to lose you should never meet for the first time an online hookup, from any platform, at your place.
As I also like very young men, and I used to live in DC when I was using Grindr, I would always set a first date at a known bar, where I knew that they cared about their liquor license and therefore would ask for ID to every single customer. This safety measure is not infalible of course, but it would significantly reduce the risk of ending in an underage situation.
I do not know if someone else shared that advice. I do know many shared this one, and I will repeat it again: YOU SHOULD NEVER PAY IN ADVANCE to someone you never met before. The few times I sent a deposit or paid in advance was to a regular, someone I knew and trusted.
Good luck in future hook ups. If you are not a hopeless dummy, you are wiser now. 

I know I've been extremely stupid, but I'd still like some feedback.
So I approached someone on grindr; they asked if I was gen. I said yes. We negotiated a price of $300.
He came over, asked for the money before we began -- I gave it. He kept saying he was nervous. Then he claimed to be 17, and was this ok with me? He said his father was outside in a car. This is a state where 17 is underage for sex. He sort of suggested that he might be ok doing something if I was ok with it, but he wouldn't even sit down, because he was so "nervous."
I asked for the money back -- even offered him $100 for his trouble. He said no, and that we were free to call the police, that he had all the texts to show I was trying to pay for sex. I'm not sure he would have followed up on it. He seemed like this little hispanic kid who might have more to lose from the police than me. But I didn't want to chance it. I let him walk away with all the money.
Incredible.
 
(Edit: btw I had met another guy on grindr and the transaction worked out just fine)

Some thoughtful feedback. You and many others gave it. Just being a piece of shit and stepping on someone over and over again is totally uncalled for. 

And I guess the same is true of assholes being assholes

Not particularly. Why is this more of a risk than any other escort? Any escort could do this to you. Even escorts with reviews.
 
My main stupidity was giving him the money up front, I think. Though apparently with straight escorts that is standard practice. 

Some thoughtful feedback. You and many others gave it. Just being a piece of shit and stepping on someone over and over again is totally uncalled for. 

Yeah, now I know. But again I guess this is where straight and gay norms differ since straight women escorts apparently always demand payment upfront. 

Haha, I wish I had had even half that much presence of mind! Part of it was that I didn’t know if he was a member of some weird gang that would come back to bother me if I pressed the issue. super unlikely, but I think this was in the back of my mind. 

It’s a good question. The thing is other scammers ask for a deposit. In this he came all the way to me and met me in person on my turf. I honestly didn’t think scammers would take that kind of risk. 
 
I didn’t report him to Grindr because it probably would have gotten my profile banned too. 

Assuming the timeline is correct in the first post, the guy asked for his fee first.  Only after he collected the money did he say he was underage and his father was outside.  Clearly this was all part of his con game since there would be no benefit for him to give people reasons to send him away immediately with no money.

I think you made the right call. I often recall the advice, “never get in a fight with a man that has less to lose than you do”. He’s picked a risky business model. If he continues, sooner or later, someone is likely to beat the shit out of him  
I am curious, though, how old did you think he was?

It's 100% the risk you take when you try to make transactions on sites where vetting isn't possible. Of course you can have some good experiences as well but at the end of the day it's about how much the risk is worth, and to me no random hookup is worth getting scammed over. 
People make mistakes. Now you just have to learn from it

Protocol for hook up apps.  Meet somewhere outside your home, even if it is just outside of you home.  Tell him to meet you there and do not say that is where you live.   No one that even remotely looks underage should be engaged.  The risk is all on you even if they are being the one driving the action.  No payment up front.  The more they request it, the more likely they are not going to keep the deal but they will keep the money.  In any dicey situation, casually mention your son the cop.  Early on and as an aside is better.  Something like, are you a cop, because you remind me of my son who is a cop, perhaps you know him.   Deep kiss early on and before you get to the place you are using.  If they balk at that, just say you are not feeling it and leave.  
I have only been taken advantage of once and that was while I was on vacation in Vegas.  Was an upsell, more cash for more astivities.  I since have specified with new providers that I do not do a la carte.  

I know I've been extremely stupid, but I'd still like some feedback.
So I approached someone on grindr; they asked if I was gen. I said yes. We negotiated a price of $300.
He came over, asked for the money before we began -- I gave it. He kept saying he was nervous. Then he claimed to be 17, and was this ok with me? He said his father was outside in a car. This is a state where 17 is underage for sex. He sort of suggested that he might be ok doing something if I was ok with it, but he wouldn't even sit down, because he was so "nervous."
I asked for the money back -- even offered him $100 for his trouble. He said no, and that we were free to call the police, that he had all the texts to show I was trying to pay for sex. I'm not sure he would have followed up on it. He seemed like this little hispanic kid who might have more to lose from the police than me. But I didn't want to chance it. I let him walk away with all the money.
Incredible.
 
(Edit: btw I had met another guy on grindr and the transaction worked out just fine)