I've been keeping my eye on the price of this as my boys absolutley love Plants and Zombies and they were so exited to hear that it is coming out on the DS.
Amazon have reduced their pre-order price to £17.99
(You also get the pre-order price guarantee with Amazon so if the price drops you will get the charged the lowest price.)
It's still £22.99 at Play and elsewhere so this seems a good price.
5 game modes: Adventure, Mini-Games, Puzzle, Survival, & the stress-free Zen Garden
Conquer 50 Adventure levels
Battle zombies in 22 mini-games, including four all-new games
Challenge a friend in Versus mode and choose your side — plants or zombies!
Make your own zombie with the Zombatar!