"That much" will fit in a medium box. Heck, a case of primers isn't much bigger than shoe box....As far as affording it, you pay now, pay later or quit shooting. Reloading components don't go bad and they certainly aren't going to get any cheaper......I have a friend that told me he bought a large quantity of powder in the 60's for 50 cents a pound...He is still using it.
Personally, I'm not worried about the LGS. If the business owner's choose to jack the prices up so high that shoppers look elsewhere it's not my fault if he closes. Sure, I don't mind a guy making a living, but won't support him in making a killing.