Walmart offers the Gold's Gym Unisex 20-lb. Adjustable Weighted Vest in Black for $38.72. Opt for in-store pickup to avoid the $5.97 shipping charge. That's the lowest price we could find by $13. It features breathable mesh fabric, a pocket for an MP3 player or iPod, and 20 1-lb. weight packets.
Update: The price has since dropped to $33.49.