Update thanks to post below by another person.
Costco has the O Cedar spinning mop system with three additional mop heads (total of four mop heads) for $38, but starting April 19th there is an instant $10 off Better deal than the Home Depot deal of the system alone for $20 (which has expired) and no additional mop heads. Mop head replacements are about $6 to $7 each.
Also O Cedar two set angled broom set for $11. Two brooms and two matching dust pans.