My best plant purchases, hands down, have been through the classified sections of aquarium communities--either boards like this or local aquarium clubs. Goatnad at this site sold me a great variety of high quality, low-light plants. I've also had success through the Planted Tank website.
joy to the fishes in the deep blue sea
55, 30, 30, 20, 10, and 10-gal. freshwater tropical tanks