One Costco employee at each new store can win $500 in cash if they correctly guess first-day sales

A new Costco in Scarborough, Maine, a week before it opened on November 17.

Gregory Rec/Portland Press Herald via Getty Images

• Ten new Costco warehouses opened in November, which means cash prizes for 10 lucky employees.
• In a company tradition, employees at opening warehouses guess their location's first day sales.
• Guesses are written on dollar bills that are then given to the winner with the best number.

November was a busy month for Costco, with 10 new locations opening up during the month...