Costco sells both the KitchenAid Professional 6-quart mixer and the KitchenAid 5-quart glass bowl tilt-head stand mixer on its website, as of 2015. It does not sell accessories or parts for KitchenAid mixers separately.
The accessories packaged with the 6-quart KitchenAid mixer are the beater, dough hook and wire whip. The store limits customers to purchasing only five of these units per membership. The 5-quart model, which does not have sales limitations in place, is available in empire red, metallic chrome and cobalt blue. Accessories packaged with the tilt head stand mixer include a dough hook, wire whip and flex edge beater.