The domestic post card rate was increased from 3 cents to 4 cents on April 1, 1954. The post card rate remained fixed until November 1, 1968 when it was increased to 6 cents.
Hamilton to Tillsonburg, December 5 1957
4 cents post card rate
Shortpaid
Edmonton to Georgetown, September 8, 1955
4 cents post card rate
Shortpaid 2 cents and taxed 4 cents (double the deficiency)
4 cent due stamp cancelled at Georgetown, September 16, 1955
Undeliverable post card
Toronto, August 1958 : No address
RETURNED FOR BETTER DIRECTION
(A bit of an understatement)