Be sure to check around for prices--Midway, Natchez, or Midsouth will probably be best.
Natchez has the rockchucker for about $85.00 this month. They are at http://www.natchezss.com.
PS. You might consider getting a GOOD (IE Mitutoyo MyCal) electronic caliper. Easier and faster to read. Best price: MSC industrial supply.