Some of my happiest memories as a child was with my father at the National Archives. Archival boxes -- Hollinger boxes -- are to me what baseball gloves or fishing poles to others. I wrote about these before but I now have a photo. Good prices, and you can buy single boxes for a small surcharge over what libraries pay. (Buy multiples of five to get the discount.) I could get the tan kind, but Hollinger grey is so soothing; it makes me happy.
And I got another shipment today.
Church archivists should consider ordering from them online. They also sell archival bond paper, which would be a good choice for important documents and perhaps certificates. Other supplies, too. Despite the name, the invoices, packaging, and enclosed catalogs are all Hollinger Company proper.
Genealogical Storage Products