Just wondering why you wouldn't have the capability to buy gift certificates on your website.
For the customer its convenience.
Fill out the form.
Decide on the value.
Customer pays with credit card.
And you email the gift card to customer.
Clean transaction.
And the bonus for you?
Offer the buyer a gift card too if they opt in to your data base.
You control your cost of acquisition.
And if they use the gift card you just got yourself a new customer.