When they gave the boot to me at my pre-op visit, I asked (naively) whether I would return it to the clinic or to the hospital. The nurse said that it was mine to keep, and that the cost was part of the "package deal" for the surgery. Realizing that I only needed it for a couple weeks, I asked what to do with it afterwards. Could I sell it on eBay? Her reply was that everyone gets new boots, noone wants an old dirty one, and besides I might be sued if someone wore my boot and fell down.
When the bill came for my pre-op visit, I noticed that the boot was invoiced for $300. Curious, I searched it on eBay - where I did find one offered (inset photo) by an orthotic shop. This one is described as "Condition: New: A brand-new, unused, unopened, undamaged item." The cost? $43 as a Buy-It-Now. And with free shipping.
I'm still waiting for the hospital bill to see what they charged me for the crutches they gave me ("part of the deal" again). I've already spotted the same ones on eBay for $8 + $9 shipping. I'll bet the hospital didn't bill me $17.
Think about this if/when you have elective surgery scheduled and can plan ahead.