Kmart offers the Kenmore Box Fan, model no. 32002, for $17.99. Opt for in-store pickup to dodge the $9.50 shipping charge. Plus, Shop Your Way Rewards members receive around $10 in SYWR credit. (Not a member? It's free to join.) That's $6 off list and the lowest total price we could find. It features three speeds and a removable front grill.
Of note, Shop Your Way Rewards members may be eligible for additional credits and discounts.