Amazon offers two M&M's Milk Chocolate 42-oz. Party Size Bags
for $17. Clip the 25% off coupon on the product page and the price drops to $12.75
during checkout. Plus, Prime members bag free shipping
. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $1.99.) That's $5 under what you'd expect to pay in local stores.