Pier 1 rarely does general coupons as it is a perk for those who open a credit card. Sometimes, though VERY rare, they will send them to people who are on their email list or have them for local events.
Just keep up with their sales and check out their clearance merchandise. These prices are generally better then any of the coupons would have been anyways and can not normally be combined. Clearance usually gets changed/added to every week to two weeks (depends on the time of the year) and sales switch out monthly.