You don’t need much luck to run the Bank of America Shamrock Shuffle for cheap.

Organizers announced one last flash sale Friday, offering $10 off the entry fee for last-minute runners in honor of St. Patrick’s Day weekend.

The sale will last through Friday only. Register here. 

The race steps off March 24 in Grant Park, marking the unofficial kick-off to outdoor running season in Chicago. This year’s even marks the 40th anniversary of the popular Chicago run.