3. Stamps and postal stationery
The Stamp Vendors shall obtain supplies of stamps and postal stationery from the Postmaster for cash; they may keep for sale stamps of any denomination to be sold at face value, and they shall be entitled to receive from the Postmaster a commission at the rate of (a) 5%, on stamps purchased by them of the following values only namely: $0.01, $0.02, $0.04, $0.05, $0.06, $0.10, $0.12, $0.15, $0.25, $0.35, $0.50, and on postal stationery of any description, and (b) 2½%, for the following values only $1, $2.50, $5, subject to a minimum purchase of any denomination and postal stationery amounting to $5 on any single occasion.