Show your spectators a 50 euro banknote, and put it inside a wallet. Zip the wallet closed, and lock the zipper with a padlock. Now shuffle the key that opens the padlock with other seven similar keys that do not open it. Invite seven spectators to freely choose seven keys, leaving the last one for yourself. Offer to give as a present the 50 euro to the person who has chosen the key that opens the padlock. Make sure that the choice of the keys is absolutely free above any doubt.
Naturally the key that opens the padlock will be always the one that is left for you!
The wallet measures cm 11,5x 10x 1,5.
In the instructions you will also find a very nice alternative presentation suitable for a mentalism routine.