I was out buying a gift for a birthday party on Sat and Joann's had a bunch of stickers on clearance. I found a cute set of farm-themed stickers with 2 of each sticker for .97. Jackson and I used index cards and in about 5 minutes had our memory game.
We've played several times. Kira's not quite ready for the actual memory game, so we've been using it for sorting activities, colors, and of course, two-handed play putting it in/taking it out of the ziploc bag.
I think it's great because I can throw the ziploc in my bag and have a quick activity for waiting rooms, restaurants, etc. And if a piece gets lost or ruined, no biggie, it only cost a buck!