Shopaholic

To unlock this achievement, you must buy 25,000 dollars worth of items in Crazy Dave's Twiddydinkies. The easiest way to get this is to buy the Imitater or the 10th seed slot, or also the Aquatic and Night Zen Garden or the Mini-Games pack depending on your version. In addition, you will have to do some gold farming to get this since it takes a long time to get all that money by playing Last Stand or Survival: Endless.

Trivia

 * There is an equivalent achievement in the Nintendo DS version called "Shopping Spree".