Best plant store, that I've been to, in Ohio is sadly Aquarium Adventure in Columbus. If you can get there early for their 50% off sale, it's well worth it.
There is a plant store that sells a lot on Aquabid but I don't see any of their auctions listed, nor can I remember their name. But they are located in Ohio and have a LOT of plants for a really, really good price. If I find them, I'll post their name up (they do have a website as well).