CHEAPER on eBay ... which is where I found mine. Calibrates instantly. Great used stuck on a brake disc to measure relative camber changes, even used it magnetically stuck on the inside of the Z06 hub carrier so that I could see relative changes while working the front camber eccentric while lying under the car ... next to a jack stand of course. Also used it against a very straight piece of composite that happens to fit inside the front of the 17" front wheels. For measuring absolute camber you must of course be on a perfectly flat floor ... which most garage floors aren't.
You can make a flat "platform" by using vinyl flooring squares to build up the low side. You can buy a square section length of steel tubing ... which you place on two "stands," I use two identical heights ratchet sockets, that you place where your tires would be. Use a level on the steel tubing to figure out how much to build up the low point. Mark that bit of garage real estate ... include how many vinyl tiles are required to create level.
