I'm 28 hours in and have over 300k. Indeed do bandit camps but to get some real money out of it you have to utilize
crafting. Disassemble all the looted weapons and find the most expensive uncommon and common items you can craft. Items of higher grades are not optimal for making money as their parts are rare. Having skills invested in crafting will make you a real billionare, but it isn't necessarry.
This is the most optimal uncommon item I craft for money. Common items will make you less money per piece, but you can manufacture
way more of them (Just look at how many common crafting parts I have).