Attention random internetters:

Does anyone with back pain have any experience with TENS units? 

I am paying $25 per physical therapy session where most of what they do is hook me up to one of these for 15 minutes.  I’ve already spent $100, which is the cost of a TENS unit in the first place!  So why not just buy one for myself?

 This back pain sucks.  I think it’s been four months now.  I am almost nearly-miserable at work, and it is pretty much on my mind every minute of every day.  I did not know just how much this can make life suck.