My sim had two easily fulfilled wishes, buy incense holder and buy fireworks. He was in the market so it was easy. He stepped into the general store, and went up to the register. When the menu came up, I clicked the fireworks, then the incense holder, then (because buying one firecracker doesn't make much of a display) I clicked the top item in the buy column (I bet you can see where this is going) where it used to say 1 (one) fireworks, and changed it to 20. Ooops. Just as I clicked buy, I realized that the incense holder appeared above the fireworks. I bought one fireworks and 20 incense holders.