I paid AU$50 for Ozito rotary tool which came in a kit with variouse attackments. The roatary tool was also on special, discounted from AU$75. By the way my dad had a dremmel which broke and all his official dremmel attackments work on the rotary tool i got. The diamond files where about AU$15 and where on special from my local hardware store.
Those where basically all i needed to make a decent quality lock pick set apart from a bench, cup of water and eye protection