M19A1 .30 Caliber Ammo Can (10"x3.5"x6.5") Removable Lid  ($5 each)
M2A1 50 Cal Ammo Can (11" x 5.5" x 7") Hinged Lid ($6 each)

Larger M2A1 50 Cal Ammo Can (11" x 5.5" x 9.875") Hinged Lid ($8 each)

M548 Ammo Can (17.25"x7.5"x14") Removable Lid ($10 each)

All are used in various condition on the exterior but are clean on the interior with good lid seals.  You can pick and choose the ones you want.

See pictures for samples.  Some are better some are not as good.