Costco Sale: Slingbox 500 $229.99 by Rhonda July 24, 2020 *UPDATE* 2/3/15. Costco has the Slingbox 500 on sale for $229.99 (after manufacturer’s instant rebate), now through February 28, 2015. That is $40 off Costco’s regular price of $269.99. For reviews … 0 FacebookTwitterPinterestEmail