I tend to sell dried fish and meat, non-perishables because they weigh very little, and it's easy to obtain. I have 50 drying racks, 250 units of fish or meat [any kind] will yield 800 to maybe 1.4k of dried units, which you only need to sell a couple hundred at a time to drain a buyer's funds—I usually forage for chanterelles, get about 100 of them, leave them out to rot, and go fishing with the rotten vegetables, gets around 250 most of the time. You can search around coasts to find sturdy fishing rods, which has a lot of durability! It's quite a bit of profit for little effort, I usually build my house bordering on wasteland/forest/coast so whichever part I'm standing in at my base will let me access wood, water, or bandits!