You have 16 cards; each with a different food item displayed on them - this is your shopping list. The spectator mixes up the cards. The spectator then chooses one of the cards. This is done twice. You are then able to tell the spectator which two cards they have chosen without you having to look at the cards. Very impressive!
This is a great effect. You can adapt the patter to suit whatever theme, using food items, you wish. The cards are printed with a food item on one side and the receipt for all of the 16 food items on the reverse.
You can talk about how you purchased these 16 items, but had to return two items due to them being out of date, or of poor quality. The spectator chooses two items, at random, and then you reveal which two items were chosen by the spectator.
As a bonus, you can then reveal that you knew the total that was paid for these two items. As an 'kicker', that is just simply genius.
Very easy to perform.