Usually at least once a year tile stores have clearance sales up to.80% off. Call a few to get their sale dates. Ours usually do it mid Sept. Also go to Habintat stores, they sell tile cheap.
You could try your local Habitat ReStore or similar, see what they have. Usually they sell stuff for crazy cheap.
Places like Big Lots and Ollies have great things really discounted to do just this. Here is a link with ideas as well.