I think a nice date might cost a little more than that. Especially if it involves eating and bouncing around a little.
I'm not sure if I should go with the night out of drug fueled debauchery as my high watermark standard because it feels like prices are awfully regional on quality party tickets // alcohol // etc and with conservative estimates you would only be taking care of yourself and that isn't really what you are shooting for.
Cubing is free but that fits into a lot of examples where it requires some amount of work // investment to be a door opener.
I dunno I like excesses and simple pleasures. Maybe I'm not the best for this. Buy a couple modular board games? Role playing manuals and some wine? People who play music seem pretty happy, I guess people enjoy playing music, does that cost a lot of money.