RetailMenot - The RetailMeNot mobile app allows you to find deals on the go for both online shopping and in store shopping.
CouponNDeal - I regularly checking this out now.
Honey - Honey is a browser extension that automatically finds and applies coupon codes at checkout with a single click.
Dealspotr - Dealspotr is like Wikipedia for deals.
DontPayFull - Verified coupons and discounts for a variety of online retailers.
TopVouchersCode.co.uk - Welcome to your favourite destination of voucher codes, promo codes, discount codes, & free shipping offers!