As someone who enjoyed the crap out of the first Plants VS Zombies, I hope it will come to Android, as right now it's just an iOS game. From the PopCap Press Release:

"Designed as an ever-expanding universe that will offer regular updates including new worlds full of new plants, zombies and challenges beyond the first three that comprise the initial game, Plants vs. Zombies 2 extends the classic gameplay of the original and provides players with dozens of all-new levels, plants and zombies. While the vast majority of the game is entirely free to play (players can face every zombie and access every level in every world at no cost), Plants vs. Zombies 2 players can also purchase upgrades and other in-game items."

Geek.com article states to unlock all the CURRENT plants in the game, it will cost you $19. But with this model, we can expect many more plants, and because it's controlled by EA, not many sales.