CostMo

 is a limited-time premium building that was released on November 20, 2019, as part of the Black Friday 2019 Promotion. It was the sixth and final prize to be unlocked in the promotion.

About
 is a grocery store near Springfield Mall where the Simpsons, Agnes Skinner, Lenny and Moe shop. The bag boys briefly went on strike causing the food supply to be cut off.

Regular
Marge
 * Marvel at Bulk Savings - 4h

Quest Based
Homer Ned
 * Play Ping-Pong With Himself - 4h
 * Flee - 4h

Trivia

 * Only one can be obtained.
 * It can be placed on grass, pavement, dirt, krustyland road, boardwalk, pier, edge of boardwalk, or edge of pier.
 * It is the second building to have the income produce donuts instead of common incomes such as krustyland tickets, cash and XP.
 * The first is the Lard Lad Donut Factory.
 * It is a parody of the retailer, Costco.
 * Since this building costs 900 donuts and produces 6 donuts once per day, a timely collection every day would mean it takes 150 days for the building to pay itself off, and profit starts on day 151.