Bass pro shop has Remington UMC 250 rnd bulk packs for $96 bux. On a side note, my M&P .380 is my EDC and my carry ammo is Hornady's American Gunner XTP's... and in all honestly, I havent experienced a failure with that brand ammo.

Remington UMC .380 Auto Handgun Ammo Mega Pack | Bass Pro Shops