http://www.smartracingproducts.com/howtobuy.html
Check this site out, I saved it in my bookmarks sometime ago.
Both Terry and I independently bought this camber gauge years ago. It was really expensive a decade ago, and worth it. It was an evolution of the "bubble gauge" that had been used for decades.
Today there are other options, but I still recommend the SmartGauge for camber measurement. It's so easy to use without having to "make do" or set up some rigged assembly or stick my phone on a hot, dirty wheel.
I've also got an ART Laser Toe Gauge from here:
http://www.advancedracing.com/laser_toe_gauge.php
It's a bit of a PITA to use and really has to have a large setup platform. I used it when I campaigned a single car, and worked from the same level garage, with marks on the floor. But I never got proficient using it at the track or switching it from car to car. It can't be used when on either my elevated setup platform, or Terry's scale risers, so it doesn't get used much. In fact, I don't even know where it is right now. I may have loaned it out and never got it back.
Instead, I use toe plates.
http://www.longacreracing.com/products.aspx?itemid=1709&prodid=7236&pagetitle=Toe-In+Plates+(pair)
These are extremely easy to use for minor setup changes as long as you are starting with a known good alignment, either from a good string alignment, or a professional laser rig. The issue is getting the thrust angle right, and keeping the caster close from side to side. FWIW, most street alignments add a little caster to the front right wheel to counteract the normal crown of the road. For competition use, we do a symmetrical alignment, which makes the car pull very slightly to the right on a normally crowned road.
