I just ordered from Planted Aquarium Central via ebay. Shipping was $6.99 for the first plant a $.79 for any plant after that. I got extra plants on top of what I ordered, and everything looked great. My vals were a bit on the yellow side, but the plants were also stuck in the mailbox for a few hours. They're doing pretty well now for the week that I've had them. I felt like they were pretty cheap..
I have also ordered from aquaticmagic on ebay (also on aquabid) and they were awesome, but they do ship from Singapore so I wouldn't get any fragile plants and the shipping itself does take a while.. They'd shipped my package within a couple days of me ordering though. I purchased anubias from them and it took about 12 days before they arrived, but only one of the plants was really yellow - the rest were almost all dark green and they're all doing well. It was a very generous amount of plants.
I guess sweet aquatics would've been a few dollars cheaper as far as the plants, but shipping for the 4 groups of plants I bought shipping was less than $9.00.. So I might've paid a couple dollars extra, but I got my plants from planted aquarium central in half the time and the plants arrived looking beautifully.