I have ordered from RoundStone seed, and I’ve been very pleased with them. Great folks, good customer service, and quality seed.
I see that you’re in Wisconsin, and RoundStone is located in Kentucky. If you’re able to, I would strongly encourage you to try get seed from a company that sources their stock from Wisconsin or a contiguous state. I think that you’d have higher odds of a successful and enduring pollinator plot that way. Genetic traits that make wildflower seeds successful in the mid south might not translate to success in your region.
If you are interested in doing more than 1-2 acres it may be worth your time and effort to talk to your local NRCS office. Their cost share programs will typically cover the cost of both seed and field preparation.
I have converted several small areas on my properties (1-3 acre portions of fields) into pollinator plots, and I’ve helped friends with converting slightly larger fields on their properties (3-5 acres). I’m far from an expert, but I’m happy to offer my amateur advice if it would be beneficial to you.