An established homestead can support itself and a family through the production of raw materials and manufacturing of goods. Basic necessities are grown or created by hand. Everything else, that can't be sourced from home, is instead purchased using funds that come directly from the income that the homestead generates. Animal products are a popular choice for entrepeneureal homesteaders. Animals can provide hides, meat, fur, milk, eggs, honey, or a variety of other products that can be sold straight away, or transformed into artisan goods.
It may take a while to start earning money off of your homestead. Markets are hard to infiltrate, and it may take a few seasons to perfect your particular product. Homesteaders will typically cushion this transition time through savings, a secondary job, or by taking out loans.