You'll be able to buy coins with real money from this week.
Brian Lindley, producer on Plants vs. Zombies: Garden Warfare has written a post on EA's The Beat where he confirms microtransactions are coming to Plants vs. Zombies: Garden Warfare this week. The basic idea is that impatient players will be able to use real money to buy in-game coins that can then be used to buy sticker packs that unlock random new character parts, potted plants, zombies, customisations and ability upgrades. While the microtransactions won't affect game balance (everything can be unlocked through regular play, and the unlocks are mainly of the "different, not necessarily superior" flavour) - it still rubs us the wrong way seeing as the new packs (that unlock the latest Zomboss Down DLC characters) are rather pricey. Fingers crossed future new packs won't get even more expensive to further encourage using real money.
"Starting next week, players will be given the option to purchase coins from the Sticker Shop, which allows players the ability to access new packs and character content more quickly - all the same content that can be earned through regular gameplay. Now you have the choice to play your way; you can play to get new packs and content via earned coins in the game, or you can purchase coins to get more of the packs and content you want right away."
Lindley also teased that more free content and updates are inbound.