You know, it's getting fairly rare that I meet a government expenditure that I approve of. But one of my spies pointed me to this site today--the North Carolina Agriculture Review. I'm not a farmer, so the articles are more of academic interest, but the for sale ads are great. If you need a tractor, want to buy a goat of want some less expensive lumber, this is a great place to look.
If you're not in North Carolina, check your state's Department of Agriculture. They may have a similar publication.