See Video Demo Below:

Effect

A precision machined and cut coin that actually folds.

The folding action allows you to put the coin into a bottle and then remove it.

The trick requires minimal practice but the shear novelty of the coin is worth the investment.

An endless list of possibilities for this trick, the double folding quarter. 

Make the quarter appear or fit into places it has no business being and pull it back out to truly mesmerize the audience.