If you want lots of cash, just tag your gambling skill when you create you character then increase it to at least 80% go to any casino and hold down the keys for example 1 and 4. Sit back and watch your credits increase. With cash you can buy books(The Hub) to increase your skills and all weapons and ammunition on sale. No need to steal, no need to barter and no need to tag skills like FirstAid, Repair, etc.