Here’s an example of variant covers for no apparent reason. This comic was some kind of giveaway with previews of upcoming Ultraverse titles. Some of them had a unique serial number — adds to the collectability, eh? I don’t remember seeing these being sold in comic shops, though.
At first I thought there was just one version of these. Then someone spotted another. And another. These are the only three that I know for sure exist.
As far as value, I’m not sure if I’ve ever bought one of these off eBay by itself. I get them packed in with a lot of other books. I’ve grabbed a couple out of quarter bins, too.