oh common.
just completed the game for another time.
1) until you get out of Fort Joy grab anything from everywhere and sell it to anyone
2) you don't need to steal anything, I didn't have bartender skill also
3) when I met first undead on the bridge outside Fort Joy (near teleport point) I had about 4000+ golds, and only now I could upgrade some items in my gear and buy few new skill books
4) same with Gareth: until the last battle you collects up to 8000 gold and spend it in Seekers camp for the last upgrade. of course, I bought some gear before last battle also, and still I had a lot of money for the last upgrade
5) btw why do you need to buy ALL the books in the game? you have memory slots and it's slightly limited, source skills useless until source points almost disappeared from the game. you'd better think about HOW TO SPEND wisely, instead of 'how to get some gold to spend it on useless shit'