Just, for the love of whatever you wish to be loved by, don't get gift certificates. Why people continue to fall for this reverse rebate scheme at the expense of friendships I don't understand, but they continue to do it.
Only thing worse than getting a tacky sweater you'd never wear from a friend is having to go down the the tacky sweater shop to pick out your own. Or let the gift certificate expire thereby helping out the tacky sweater shop even more than if you'd gone in to buy a tacky sweater.