Groupon offers this Large BBQ Grill Cover for $21.99 plus $3.99 for shipping. That's $33 off and the lowest price we could find. It measures 61" x 24" x 48".

They also have the Small BBQ Grill Cover for $18.99 plus $3.99 for shipping. That's $26 off and the best price we could find. It measures 49" x 24" x 36".