Although that's before my time, it does bring back memories of H.E. Harris & Co., when they were in Boston, and Sears (then known as Sears, Roebuck & Co.) when they sold stamps.
If you're interested in dating that package, here's an ad taken from Boys Life Magazine in August 1951 advertising the product:

While $2 sounds like a reasonable price, you have to remember it quite a sum back in 1951, in fact, according to an inflation calculator, it's equivalent to more than $16 in today's money, which would have been quite a bit for a box of stamps geared toward kids. (Of course, Sears apparently sold them at a discount of $1.50 based on your scan.)