Get a £10 gift card for a fiver.
Don't forget cashback:
Quidco - 7%
TCB - 5%
Validated email not required (use garbage), same paypal can be used.
1) Pay for deal as new user (Scroll down)
2) Use PayPal (can be the same account)
3) Goto My Orders and note code + pin
4) Redeem at http://starbucks-groupon.cashstar.com/claim/
5) Transfer amount to your proper starbucks card if required
6) Delete NEW card if required
7) Sign out of groupon, return to deal page and goto 1) :)