Bostik 50 lb. White Big Tile & Stone Polymer-Modified Large & Heavy Tile Mortar, $36.99 USD/Box, LL Flooring (Lumber Liquidators)

Designed for setting porcelain, ceramic, and stone tile indoors and outdoors. It's ideal for installing tiles on plywood, backer board, and approved waterproofing membranes, as well as existing ceramic and vinyl flooring. Suitable for interior and exterior use, it sets all large size tiles made of ceramic, porcelain, granite, slate, marble, limestone, and dimension stone.