The Mercedes tools would be ~$1300 from a wholesale source (you need to buy front tool, rear tool, and a set of plates.) There are aftermarket tools which are cheaper, ~$500-$900 for the kit.
Or, you can rent it from Performance Products for ~$90 plus S&H both ways (~$125 total), with a ~$550 deposit. I rented it and it did work, although I don't like the "SIR Tools" brand compressor they have - it is not easy to get the center shaft "hex" to seat in the top plate. The older style Mercedes tool (no longer sold) worked much nicer, and was only ~$500 at the time. The new style is redesigned and would probably work great, if it weren't so damn expensive...
HTH,