Kind of nice: If you buy 200GB of Google storage for $50, you'll get a free 4GB Eye-Fi card. Since the card's $60, you could also look at it as "buy an Eye-Fi card, get 200GB of Google storage."
All in all, it's pretty simple. Just sign in with your Google account, drop in your credit card digits and tell 'em where to send your card. (Oh, and yes the 200GB is a yearly subscription. So the first year pays for itself, to be more precise.) [Google]