A gift certificate can be sold for a lower price than the amount it will later redeem for. For example, you might sell it for $200 but allow it to redeem for $250. The sale records the lower purchase amount, while the higher redemption value is credited to the customer (or the intended recipient). When the certificate is redeemed, the credited amount is used toward the purchase, and any remaining balance can be paid.
Before proceeding, confirm that you have created a product profile for the Gift Certificate in the Product List, that it has been marked with the Gift Certificate setting, and that it is designated as non-taxable. Additionally, you can keep the Retail/Cost at $0.00 and enter the Price when it is added to the invoice.
Gift Certificate Options:
Selling
Create an invoice for the customer who is purchasing the gift certificate. Adjust the amount in the Price field for the purchase price (A) and record the same amount as the payment in the correct payment type field, either Cash/Check or Credit Card (A).
If the customer purchasing the gift certificate will also be redeeming it, enter the redemption amount in the Gift Certificate field (B) at the bottom of the invoice to credit the customer's account for future use. This amount will appear as a credit to their account (C) in parenthesis.
Alternatively, if the certificate is for a different recipient, the redemption amount can be posted as a payment to the recipient's contact profile instead of adding the amount to the Gift Certificate field (B) shown on the invoice above. When posting, select Gift Certificate from the Payment Type drop-down, and a memo referencing the original purchase's invoice number can be included.
This amount will appear as a credit to their account. 
Redeeming
Upon redemption of the gift certificate, a new invoice should be created for the products being purchased. The Previous Balance field (D) will display the redemption value of the gift certificate credited to their account, which is indicated in green. There is no need to record a payment on this new invoice unless the total exceeds the gift certificate value, indicated in red as the New Balance (E).
For instance, if the recipient has a redemption value of $250.00 (D) and purchases the following items totaling $263.22 with tax included, a new balance of $13.22 (E) is owed. If they decide to pay this amount, record the $13.22 in the Cash/Check or Credit Card field. If they are not paying the remaining balance, nothing further needs to be done, and the invoice can be saved. When payment is made on a future date, do not edit the invoice, instead, post it to their account for the remaining balance.
