I have setup a system before for a client which has used purchasable coupons as a special product class to achieve the same results. It allows users to purchase a coupon as a product (which you label as Gift Certificates). A rough guide is below, as best as I can remember it:
After installing Ubercart v3 and the UC_Coupon Module:
Go into coupon modules' settings and allow coupons to be purchasable.
Go into the Coupon section and create some coupons you want to offer on your website.
Ideally you can use the options that coupons provides to get a granular selection of what you want to discount on your website and how.
Make sure when you're making the coupons that you select the "can be purchased" sounding option.
I don't remember exactly how it's phrased.
After that, go to
Store > Product Classes, create a new class of product called "Gift Certificates" and assign varying prices as product attributes ($5, $10, $50 etc..).
Or you could make a separate product class for each price/style of certificate, your choice.
Either way, once you make the product class(es), you can use the created class to create as many "Gift Certificates" as you wish just like any other content type, you need to:
- attach the coupon your selling to the product using the Features tab on the Edit Product screen.
This should allow the same effect of a gift certificate using coupons as a product you purchase.
The coupon module offers some powerful ways to create some nifty promotional sales for your products / services etc if you play around with it.
Edit: The only situation this wouldn't work without some custom coding is if you wanted to offer a "gift certificate" at X amount, where X = price is set by the user.