This is a good source for a variety of seeds, but it is a great source for wildflower seeds. They sell seed mixes that are customized to the region of the U.S. that you live. Prices for shipping are good.
If possible, I think everyone should sow a patch of wildflowers. I would consider it part of my Zone 4 (see my post on Zones). Not only is it beautiful, but it provides a source of nectar for beneficial insects and generally increases biodiversity.
Wildflowers in Temblor Range, California
A small Wildflower Patch... easy!
Look into it creating your own!