I think he was meaning the magnetic base and dial indicator. These can be relatively cheap or really expensive. Not the base itself but the dial indicator. The cheaper they are the less accurate they are, however you don't need something super accurate for what Weldandgrind is mentioning. Perhaps I'm misunderstanding the 'how much does the tool cost" thing..
Here are two examples from princess auto, which would be quite cheap.
http://www.princessauto.com/tools/me...flection-gauge
http://www.princessauto.com/tools/me...-magnetic-base
I'm starting to get wise to the Gio business plan. Sell product cheap, kill people with replacement parts cost.
I never thought I'd say it, but I'm missing my engine shop with all the tools, lathes, grinders and work areas now that I have these things!