I'd steer clear of used ones; never know where they've been!
Since probing isn't a sterile procedure it really doesn't matter. If you could get used probes free or at a discount they would be fine as long as they were washed and properly disinfected.
-adam
Click Below to Fight The National Python & Boa Ban
"The world is a dangerous place, not because of those who do evil, but because of those who look on and do nothing."
- Anna Sewell, author of Black Beauty