Actually, Monsanto also sells most "conventional"(non-GMO) seeds. It's very difficult not to deal with them, as they have a near-monopoly. If you're going to look for evil, look there.
no one is making you buy seeds at all. non-GMO seeds don't come with "no save" agreements. if you are a farmer, just do what farmers have done for thousands of years: get your seeds from this year's harvest.