March 18 and March 19, what will you bring in to “fill er up” with Slurpee? This is the day where you can bring in any cup from home and fill er up and just pay only $1.50. The cup “must fit upright through an in-store display with a 10-inch-diameter hole,” the company says. That display below will be there, if your cup doesn’t fit through that hole, then it’s a no go. Start time will be 11am to 7 am.