For what it is, it seems overpriced, but it's saving me a bundle down the road;
When we took it out of the package, I thought there was no way it was going to fit my 4 year old son's thumb because it looked really small.  That's where the spandex comes in...  He loves the color green and I don't sew, so this was alright for us.  It comes with a chart to keep track of how many days/weeks they have gone through without sucking their thumb.  If your child is 2 or 3 or even a young 4, this product will not be as effective.  It only works if you know what buttons to push to get them to quit.  It serves as a reminder and helps them at night.  We used bribery in the form of toys at the end of each week.  Now that we have completed 6 weeks of non-thumbsucking, he really doesn't need it anymore, but it's sort of a security blanket.  It's a little worn, but not falling apart.
The sooner you can get them to quit sucking their thumb and make it rewarding for them, the better off they will be.  No more thumb in mouth right after touching a grocery cart loaded with germs, or worrying about their permanent teeth coming in like Tow-Mater.  In the 6 weeks we have been thumb-free, the gap between his front teeth has closed and his teeth have set back into correct place.  This will not happen after about 5-6 years old.  It's also the most humane and pain-free way to break the habit.  Don't wait until they are 5 or 6 and the habit is fully ingrained.  Get this tool, or something similar and go for it when they are at least 3 or 4.  Any earlier and they won't understand or have the ability to make that kind of commitment.
Yes, it's overpriced, but it's saving me a fortune in dental bills later on.  So is it really overpriced?