For friends and family, e-mail should be personal, playfull and funny. I would notify them that i've sent them a surprise on their mail and they should check all their folders (mails with links often go to spam), and i would write something like this:
I know how much you like shopping, and as a small thank you for your friendship and love, i give you this $12 Gift card to check out my new web store. :) You should click the link and then enter the code i just sent you, enjoy!
