gift cards for their Google Play store that could be bought at stores. Considering that Google is mostly in the online business (you don't say??!!) it was expected that you would be able to buy these gift cards online. Now you can.
If you go to the bottom of the Play store, you should see "Buy Google Play Credit." Currently, you can only purchase credit for your account- but we expect being able to give credit to someone as a gift to come soon.