I use four a day on the fortune cookies in ACNL because I don't have all the items yet, I sure have gotten a lot of Wii balance boards and Toad hats in the process. Then for the other 6 (or more if I feel like bumping the system up a day) I roll the dice on a possible new puzzle piece in Streetpass (most times it's an unneeded piece). I think the find Mii game and the Angler game are fun too, but I just play those with street pass people even though they accept play coins too.