When I was a TA at Austin Community College, we ran a Benchman MX. At one point I priced new tool holders. They wanted several hundred per holder.
Since it's an R8 system, have you considered going to Tormach's tooling system instead? It would be much cheaper. It would preclude the use of the Benchman's ATC, but that's no great loss. If my experience was any indicator, it's a very unreliable ATC.
I'm assuming that your Benchman does have the power drawbar. If you don't have that, the TTS won't be as big of a help.
The Benchman itself is a great little mill. Linear rails, servo drive, and a builtin fixture plate.