I bought all of the weapons, and some bait, but everything else is found throughout the world for free.
As it stands, i am almost done with West Elizabeth, and I have about 12k. WTF do I spend it on? I guess a lot of it is betting money - won a lot of dice and high stakes poker. And I did 1 round of selling all my skins when I went to Mexico, as I saw no reason to hold onto anything.