I haven't made my own rage before so I might be way off in my thinking but how do you put the yarn through the foam? If there is a special tool required for this then you should also sell it so people can set up the rags. I think the idea of being able to make your own is very appealing and also allows the person to mix and match colors or to add different things. I'd say go for it-just keep the price reasonable so people are more likely to pick it up.