Gift certificates/vouchers are now available at Material Squirrel Wings. You will be able to buy gift certificates and give them to your friends/loved ones/tiny squirrely minions and they can redeem them for wings. The gift cards are ONLY redeemable at the Gift Card Vendors in the gift card section. You cannot redeem them at the regular adboxes.
Here is the gift card vendor section location in world.
I have a small booth of angel wings at the Christmas themed sim - Winterstock. And also, this angel halo for only 1L. So go take a look and do some shopping.