I can go on ebay and buy a brand new blackberry for $160?

I paid $100 for my Blackberry curve and had $7 insurance put on monthly which covers anything. Most "problems" or "accidents" it covers I'll pay $100 out of pocket (such as water damage, stolen, etc...)and there a few it covers where I would only pay $50 but seem highly unlikely they would ever happen.

ALSO, Will they activate any phone for me. Lets say I drop my phone in the tub with no insurance on it and go buy one on ebay. Can I just go into Sprint and have them activate my new phone with no strings attached? I'm aware there might be an activation fee but does anyone know for sure?