Mountain View-based Coupons.com, the online coupon printing site, said today that it has acquired UK-based Couponstar Ltd.. Financial terms of the buy were not disclosed. Coupons.com already owned 50 percent of Couponstar, which was a joint venture. Couponstar was founded in 2002, and allows European consumers to print their own coupons. As part of the acquisition, Coupons.com said it will merge the two companies into a single, global brand. The buy comes shortly after Coupons.com raised $200M in funding.