The very best place I go for Asclepiads (family of Huernias and Stapleas) is 'Miles to Go'. They have a large list and very cheap. Bob Smoley's is also a good place. He died in May and his wife took over and is having a difficult time with it. I hope she doesn't sell out or shut down the business. He (she) has some rare types and is also very reasonable.
Tiffany gave good advise. We have been have a lot of rain this week and my jades are sitting in water that I have to drain out after each rain. Even when dry, I water very little and as soon as I water, it pours right out so I have to have collection dishes under them so they can get some water. I use a very gritty mix with them and since I started, there seems to be a big improvement in them. Also when hot and in there growing season, they need much more water. In fact in winter months, I don't water them at all. Early spring when sun is more, I start to water them.