The Old Glory buildings are included in the Old Glory Army discounts. So you buy OG army membership for a year ($50) and then get 40% off, if you intend to buy in bulk it's well worth it. Even better if you have a contact south of the border who can collect or have shipped to.
I'm lucky enough to be able to attend the HMGS(E) shows so I order and pay in advance for that I get 40% off, no shipping and no taxes, then I collect at the show.