We have a company called "If It's Paper". It is a small store that has school supplies for teachers; paper products for parties (not like Party City); paper-type office supplies; gift wrapping supplies; you can order engraved, etc invitations, etc. They do have a website as well. We usually buy a 250 count box for around $15ish. They are the A3 envies and are nice quality. Check those stores out in your area as well.
100 projects in 100 days spending only a minimumal money = 50/100 & $0