We went down this route, and it's one of my big regrets. Was AU$2 a tooth and a wish, which started as an easy and cheap soft toy (think a couple of bucks max). But it's turned into $2/tooth cumulative, ie. Tooth 10 gets $20, tooth 11 gets $22 etc, and a wish.... Cue late night runs to Kmart and lots of grumbling about why we are doing this.