If they are truely circulated IKE's, they aren't worth anything but face value except for a few folks who are willing to give a small premium over face to get one.
ebay is a lot of work and their fees and postage eat up any profit. If you can find some 1973's (issued only in Uncirc Sets) or silver ones, then you can get a decent premium for those. I was able to get a bag of $1000 a few years ago and ended up spending most of them. No 73's or silver in the lot.