Home Depot offers the Progress Lighting 50 CFM Ceiling or Wall Exhaust Fan in White, model no. PV001-30, for $22.25. Choose in-store pickup to avoid the $5.99 shipping charge. (Amazon charges the same with free shipping for Prime members.) That's the lowest price we could find by $16. It features a 4" duct adapter and 4.0 Sone rating. Deal ends March 31.