These folks offer a nice selection of the more common garden varieties as well as some easy to keep house plants, all at reasonable prices.
As a side note, their outdoor section carries Christmas Trees at that time of the year. They also have roses at reasonable prices at Valentines Day.
I've gotten their mums in the fall, best prices around. And bought a beautiful fern and some herbs for the kitchen window.
Staff is nice, folks know their plants and its all at the Quakertown Market, which is very convenient. Plenty of parking.