2-3 boxes?
The **** man, you buy it by the crate or pallet online. Back in college I'd buy 20k rounds of 5.45 and have it shipped to my part time job on a pallet.
I didn't need 20K rounds of 204 Ruger, 7mm-08 and those Colibri 22's without powder. Online is great for bulk but it also serves you well if you have an obscure caliber not readily available in most places.