Today only (6/24), get a medium Famous Slushes for only 79 cents (Reg. $1.99) at Sonic Drive-In. You save 60% off the regular price for this frozen drink. This deal allows you to buy up to 4 medium Famous Slushes for this low price. Try the POWERADE Mountain Berry Blast Slush or Green Apple Slush for only 79 cents. Sales tax is charged in most states.