I rent rooms in a hairdressers and they had one. It was a proper industrial sized gym one. She constantly put offers on and nobody really came to use it :-/
In saying that, there's a company in a town close ish to where I live and they're just a power plate company. They offer 30 sessions for £30 (or something like that) and after the sessions are over, they measure how many inches you've lost.
Do you have a business fb page? Why not put on a discussion or a status and ask your clients if they'd be interested? This is what I do for feedback and it really works for me.
Hope this helps xx