alginate/prosthetic cream
Alginate can be found at most dental supply houses. Do not get the extra fast set, rather, regular set, if you can work with that. Special Effects Supply sells the prosthetic cream, which has a longer set time. Pink House is the best. They have an alginate that has a 6-8 minute working time.
plaster bandages
Medical supply houses sell these by the case in different widths. Expect to pay around $30-40 per case of 12 rolls of extra fast or fast set, 4“ widths. If you can get 6”, then cut them down to 3“ widths. They can also be found at Pink House. Do *NOT* get the “Rigid Wrap” found in craft stores. It's overpriced and dries too slowly. You'll get a better deal buying the medical bandages by the case.
plastic sheeting/tarpaulin
Hardware stores and garden supply sell this, which is quite useful for keeping the alginate and plaster pieces from littering your floor, as well as protecting it from spills from the above.
bald cap
Found at most costume shops, you will want the thin kind of cap, rather than the very thick kind of thing. Woochie sells this, but it's not recommended that you use this. Just a cheap vinyl bald cap will do. If you cannot find this, saranwrap can do in a pinch.
vaseline/petroleum jelly
This should be a standard part of every kit, to help keep the alginate/cream from sticking to facial hair like eyebrows. You can find this just about anyplace.
5-gallon bucket/15-lb bucket/BIG mixing bowl
Great for mixing the alginate/cream and ultracal. Quite indispensable, really, when you're doing all this work. Found anywhere…
Ultracal 30
You can find this at some building supply stores. Some will have the 50-pound bag, while others will have the 100-pound bag. The stuff is cheap, though. Get someone to help in carrying the 100-pound bags out of your car! This is *VERY* hard stuff, and is also known as gypsum cement. You may find the equivalent at your local hardware store. However, avoid hydrocal, as it is not as hard as ultracal, maybe being as soft as plaster.
victim
Need I say more? The ubiquitous victim, the one being lifecasted.
location, location, location
A place that has lots of water with a trashcan can do wonders. A kitchen can do when it's cold outside. If you wish, and it's warm outside, do it out on the porch or deck on top of a tarp or plastic. If you want lots of space, your garage is pretty much a perfect spot.