I'm not sure about anyone else, but I've never bought mods out of the Mod Store. They seem WAY overpriced. Like college degree from Sanford Brown overpriced. (Google it if you don't get that). I have ...
I like the Mod store as it is, though I wouldn't mind seeing more mods selling for credits vs. crystals. As for selling mods by accident--that sucks. I don't think I've done that before, but if there is a way to help prevent that from happening, that would be cool too.