I suggest you find high demand items, such as food, pots, weapons, etc. What I do, I buy the item for max price to find the selling price, then sell it for lowest price to find the selling price. but, to be good, you have to check the prices every few hours to see if people are trying to compete with you, which WILL happen. I currently making 10m-20m a day flipping with 450ish mil. Would be a lot more, but I only manage to check my flips twice a day. If I was checking 10+ times a day, I'd make an easy 30m-50m a day.