Little machineshop has an "economy" DRO for $450.
http://www.littlemachineshop.com/pro...ry=-1536942993
If you can solder, you can build your own from a shumatech kit for around $125.
http://www.shumatech.com/products/dro-350/index.htm
You can always get one on Ebay.
Later Hoss
http://www.hossmachine.com