Step 1: Place a Card You Will Remember on the Bottom of the Deck
In this case, I chose an ace card.
Step 2: Spread Your Deck
Have the other person take a card. Keep the card you picked still at he bottom. If they pick your card that you remembered, hopefully you remembered the one before it.
Once they have taken their card, don't let them show you.
Step 3: Have Them Put Their Card on Top
Step 4: Split the Deck
Have the other person take the top half of the deck and place it down. Then you take the other half and put it on top of they half they placed down.
Step 5: Their Card
Now, turn over the cards one by one starting from the top card. Once you see your card, say to them the next card is their card. Flip over your card then expose theirs. Done. You just won $20!!