Harbor Freight has a "coupon" for $3 plastic ammo cans. Normally $6 for this "Bunker Hill" brand, and normally the name brand, Rangemaxx, is ten bucks.
The coupon is good through Feb. 29th (it's a leap year). Limit of 5 cans per coupon, per person.
I think Harbor Freight gives out the coupons in the store, right at the entrance. But I got mine in a full-page ad in some gun magazine. G&A, I think, or maybe it was the NRA's magazine.