Take an open packet of five sticks of gum out of your pocket. Tell the audience that you have removed one stick of gum and replaced it with a folded up dollar bill. Pick four volunteers from the audience and offer them a free choice of any of the five sticks of gum. Keep one stick of gumb for yourself. Offer to trade sticks with anyone who wants to trade then tell them to open their wrapped stick of gum as you open yours. Peel back the silver foil to either side and remove the dollar bill saying, 'Looks like my lucky day.! You should have traded when you had the chance.' (Or shouldn't have, if they did.)
Fold a dollar bill until you have a flat packet slightly smaller than the stick of gum.
Put this is in your pocket with the packet of gum.
Reach into your pocket and pull out the gum while palming the bill between your hand and the gum where it can't be seen.
Have the spectators select four sticks of gum while you keep the remaining fifth stick.
Allow any of the spectators a chance to trade their stick of gum for yours. If they do trade, take it out of the hand that holds the folded bill.
Put this stick of gum, or the one you traded for, back into that hand while sliding it between the bill and your hand. Make sure the bill is now facing you on the side of the packet that opens.
Open the wrapper on your stick of gum far enough that you could pull out the gum but instead slide the folded bill up from below so that it appears to the audience that it is coming from inside the wrapper. As soon as the audience sees it, crumple the wrapper with the gum inside and casually put it in your pocket so that you have both hands free to unfold and display the bill.
Tell your audience that you wish them better luck next time and, because they have been such good sports, they can keep the gum. Then put your bill away safely in another pocket.