Seeds are pretty cheap, in comparison to all the costs of farming. Depending on the plant grown, seeds can be a few pennies per plant or a few plants per penny.
We save as many seeds as possible, although the strict guidelines of having seed isolated is not something we adhere to. Garlic is going in by the individual clove, leeks are in, carrots, radishes, turnips, salsify and other cold hardy vegetables. There are herbs that can last all winter, those are going in too.
The current work crew is comprised of a couple of pens: one with a pair of Hereford pigs, one with a flock of 50 mixed fancy egg layers, and a few white leghorns from the hatching program thrown in. They are tearing it up for replanting, with seeds going in the ground every day. Yup, in October.