I have ordered a lot of plants in the past few months from quite a few different places. Some were commercial and some were hobbyists. My absolute favorite place to get plants has become Planted Aquariums Central.
They ship fast and their packaging is great. They wrap the plants in wet newspaper, put them in a sealed bag, wrap the bag with fiberglass insulation, and then wrap the insulation with newspaper. The plants I just got even in my freezing weather came in fantastic. All of my orders with them have contained beautiful, healthy plants.
My favorite thing about them though has been the size of the portions. The order I just received was for Italian Vals. I ordered 12 and received 20 tall lovely plants. My most recent order before that was for Rotala Rotundifolia. I think I ordered 32 stems, which to me sounded like a lot. I hadn't realized just how fine a stem of this plant is though and was thrilled to find out that I had been sent too many stems to count. I seriously was probably sent at least a 100. And it turned out I needed that many.
So if you need plants, this truly is an excellent place to go. It's not often I find somewhere that gives such great service that I feel like being a free salesperson for them, lol, but this is one of those places.