pile of cash+bell boom is a cheat tool, since it will always sell higher than it costs to make. literally prints money. but also, good luck getting those stars to align
outside of that though, on a more realistically available option, iron recipe diys sell decently, imo. one moneymaking strat I had during early gameplay was just to keep all the iron nuggets set aside, and then when a diy that only took them showed up for hot items, I crafted as many as I could to then sell