An advertiser inquired to pay annually vs monthly, what would be the easiest way to set this up? Adjust the store to add an annual option, then allow them to upgrade to a different payment option or Just have them buy a gift card to them and add that card to their account future ads would deduct from the gift card?

 

If this is something that you are going to extend to all your advertisers, creating a product would be easiest then you can upgrade them or have them upgrade.

If this is a one-off, you could instruct them to add account credit as that will automatically add to each renewal.