got 2 propellers cheap... but should I keep or sell 'em?

Sorry for the brief post and inadequate example, I was busy doing Dad stuff at the time. I'd like to play with analog sensor I/O, especially with electronics recycled from old electronics, toys, computers and computer parts. I'm sure most of you here are Arduino fans and that's what I'd like to start with but should I keep one of the propellers considering the $9.95 price?