I'll admit that I can't answer too many of your questions, as I've not worked with this material personally. However, I have an (absolutely awesome...) AP 3-D student who wanted to work with this and he ordered and paid for his own supplies as well as the small "kiln" in which this is fired.
I'd think that the cost would be prohibitive for a large class, but I haven't really investigated it. The kiln/small firing pot scares me--ha--and I make the student do his firing outside. A measured amount of fuel is placed into the bottom of it, it's ignited, and it burns at something like 1600 degrees for approximately 10-15 minutes. During this time the clay burns off, leaving the silver. Pieces that come out are covered with a "dust" which must be lightly sanded off.
So far my student has designed and made a ring and also a pendant. After the Christmas break I'll try to take some pictures of the finished pieces and get some more information for you.