This is a clever idea but probably something you won't use often.
If a spectator signs the coin
you can't hand them the holder once the coin is inside... you have to tear it open first. If you
sign it then you can hand it out sealed inside.
This is the kind of trick you expect on a DVD
full of lots of different tricks and ideas to play with. It is not good enough to be a stand alone
effect.
For the same money you can buy much better effects. Add five or ten bucks and you
could buy a penguin live lecture or another DVD which would contain lots of effects all of which
would be better then this.
All in all, it is fun to play with, but there are so many better
effects you could buy with that amount of money. This should have been put on a book or dvd with at
least 7 or 8 other effects.