Yeah, there's really nothing to spend money on besides ~4K in weapons, and then the occasional flask of snake oil or medicine, if you happen to use it. (I use medicine a lot because I'm always charging enemy positions head on. I want close range fire fights so I can see the Euphoria engine in motion when bandits go down from rifle shots.)
In my second playthrough I tried to extend my money usage a bit by buying all my ammo, but even that doesn't really stretch it all that far. I've got 4K in my pocket again...
The annoying thing about that is that several times you have to do missions because the NPC in question has no money. (West Dickens comes to mind.)
So he makes you do a horse race to get him money, when I've got FOUR FRIGGING GRAND IN MY POCKET. Why can't I just give him the 1000 bucks he needs and skip the stupid horse race?