Thrift Mart in Irving, TX
on Irving Blvd, near Nursery Rd
There are two separate stores in the same shopping center-- one has furniture and the other has clothing. The clothing store is always hit or miss-- I always either find absolutely nothign or a small mountain of clothes. They have pretty frequent 50% off everything sales... If you sign up in the store, they'll send you a little postcard to let you know. :) Reasonably priced stuff.
It's also next to a Salvation Army store and across the street from Irving Thrift.