Costco Clearance: Cub Cadet 21″ Lawn Mower $349.97 by Rhonda July 21, 2020 6/3/15. The advanced InStart lithium-ion battery technology delivers a reliable start-up so no more cord pulling, priming, or choking – just push a button and go. Costco has the Cub Cadet 21″ … 0 FacebookTwitterPinterestEmail