When I was a kid, I used to LOOOOVE this beat ´em up game called River City Ransom for Nintendo. You could play solo, or 2 player, as two friends who would go from high school to high school fighting different gangs to get back your kidnapped girlfriend. But along the way, you can save money and power up by going to diners and bookstores. The bookstores sold books that had techniques that helped the characters attack better.
The game has been reiterated a few times throughout the years, and they even had a direct sequel that came out on Steam a few years ago called River City Underground. Unfortunately I never played that one as I was never much of a PC gamer and it wasn´t ported to consoles.
Here is the trailer. I still look at it from time to time hoping that one day it gets ported to Playstation: