Well this post blew up way beyond what I was expecting. It looks like I was voted Not The Asshole. There’s over 5000 comments. I couldn’t read them all, but I did read a lot. Just to clear up some things.
I left somethings out because I didn’t want it to influence opinions and really wanted it to be about me buying a guitar at significantly lower market value vs the people in the story.

I did include the fact that the guy was harassing my wife at work not to make the guy sound bad, but because I thought it was relevant to the story. Here’s some specific details I chose not to include:
The guy and his dad were not close at all. So those people saying he was grieving and I took advantage of him, that is 100% not the case.
When I went to get the guitar he was telling me he hadn’t talked to his dad in six years and was actually annoyed he had to deal with a funeral.

The dad bought the guitar new and never played it. Luckily it was stored in a closet and not in a basement or attic.
There’s no issue with the wood or electronics. It plays like a dream and I couldn’t be happier. I am not selling the guitar to the son or anyone.
It will be with me for a long time. I’m in my 30’s so maybe in 30 years it will find a new home.
I would have MAYBE considered giving the guy more money or giving him one of my guitars to sell on his own, but I decided not to do that after he left a terrible voicemail on my phone the day he found out the real value.

He demanded it back like he was entitled to an object he sold fair and square, called me a POS, called my wife a POS and said he would “do bad things” if I didn’t sell him the guitar back.
And to those people who say they would have told the guy the real value. That’s a load of horse shit.
If you went to a garage sale/estate sale and saw an item worth $5000 priced at $50 there’s not a snowballs chance in hell you would walk up to the homeowner and tell them they mis-priced it.

You’d buy the item and then tell all your friends and family what a great score you got! Don’t even kid yourself like you wouldn’t do that.
I don’t feel bad about buying an awesome guitar at a steal of a price. I was curios what others would think and it looks like I’m not the asshole so thank you reddit.
I can play the guitar with zero guilt now. Not like I felt guilty before, but now my feelings are justified.
You bought it fair n square
I am 100% in agreement with you. All these people talking about returning it is FOS he was so busy being spiteful that he didn’t even bother to research. He had receipt so he was well aware of the specifics. Should have done his homework. And your analogy about the garage/estate sale is correct,even if he sold it to a pawn shop or antique dealer. His loss tell him to leave your wife alone and take it as a lesson learned
Just like the lady on Antiques Roadshow who purchased the little table for $25 at a yard sell and it sold at auction for $541,000.
If someone has an item and doesn’t bother to determine it’s true worth then that’s on them.
Keep the guitar, enjoy it and the fabulous deal you made. You don’t owe the seller anything.
THE OTHER GUY WAS A BIGGER ASSHOLE BUT YOU HAVE NO MORALS
YOU USE THE EXCUSE OF HIS TERRIBLE BEHAVIOR TO CHEAT HIM
YTA. You took full advantage. That man may not have anything of value from the father, close or not. Liquidating a loved ones things isn’t easy, nor is paying for a funeral. He was being kind thinking of you when he saw the guitar and the fact that you might buy it from him ( I’m sure he has to get rid of a TON of stuff, most likely at a low cost or free) this may well have been the ONLY thing of value. You should have let him know the value, you kept it secret and scammed him out of what might have been his only chance of inheritance. The fact that your wife has to see him and work with him after you pulled such a move means your an AH husband too.
I’m with you on this Sir….NOT the asshole. The guy told you a price and you paid it! It’s not your fault you knew it’s value…..and you have EVERY right to get this jerk for harassment
Well the seller did not do his due dilligence. In other words. He didn”t care when he sold, he didn”t really give a crap about his dad’s stuff. So, he screwed himself and I would not give it vack.
Naaa, fuck that guy! He could’ve easily researched this on his own to sell it at a higher price.
You are 100% unethical, immoral and essentially a horribly selfish jerk.
You should be ashamed but are entirely too self centered to have any kind of awareness or decency.