most if not all of these questions have already been answered on one of my threads here:
http://ball-pythons.net/forums/showt...er+dwarf+retic
For the highlights of the OP post:
Anery, Marble, and Tribal are the only mutations that have been attributed directly to super dwarf origins. However, Anery is also from Jampea origin - so this one can be hit or miss since a lot of people have hit anery morphs from Jampea in the last two years or so.
Albinos that are currently on the market are usually going to be either 50% F2, 62.5% SD, or 25% SD. Matt over at Monster Krew has some 75% SD stuff in his "sin" Black Pastel project if you want to guarantee some smaller stock at a slightly higher price if he has any available.
Anyone can keep super dwarf retics. I'm just going to say it. Reticulated pythons have been captive bred to a long enough stand point that any keeper with solid knowledge of snakes can make it work well. A super dwarf is a great alternative to the big guys but with trade offs such as "Small Snake Syndrome" where they can be small snakes with big attitudes, or highly flighty when they want to be. My pure SD anery Kalatoa was more like handling a corn snake. 4 years old 5' long and never set still (he's in California now with his original owner who wanted to buy him back).
Prices are up and down on super dwarf stuff. The lower the price, the higher the % of mainland found in the animal typically. Stephanie at the snake pusher produces some super dwarf amel stuff, her 25% SD Amels, sell for 1/10th of what a 50% F2 goes for, and with good reason. Its a lot more work and smaller odds to get the 50% SD F2 clutches. 850 is likely Bob's pricing on what he considers SD, which is probably a SD het albino, to a dwarf albino (which is likely a 50% dwarf). Resulting in a mixture of Dwarf / SD blood.
50% SD still get big. 12' females are not a rare thing. My 50% SD male tiger who is an F2 is over 10' at 7 years old. While my female f2 50% tiger from another breeder is only 8' (barely). It's a gamble! But it's worth it.
Make sure to check local laws. Super dwarf and dwarf still follow under all the mainland laws as they still belong to python reticulatus. As of right now, you can not bring them into Texas or Florida (though we can ship out with USARK protection still in place). You can cross any other state line with them (under USARK protection if you were a member pre-ban). Some states require controlled snake permits (texas). Some requires more elaborate permits with insurance policies and caging requirements (ohio / Florida) and some places fully ban them (New York City).