Here is my Zephyr Gas "Profit Sharing" stamp book. The book says you get a stamp for each 25 cents you spend. There are 140 stamps in the book ($35 spent), worth "$1.15 in Trade." That may not seem like much, but it is a better return than most of the current "reward card" credit card points deals.
This Zephyr is a brand from J.D. Streett with a home office in St. Louis, MO.