Ah. They may have been.
In 1926, Akro presented 11 marbles for a dime as a very hard to beat offer.
In 1929 their wholesale prices for 1000 marble lots ranged from .355 to 2 cents per marble, depending on style, just for the 9/16" size. Up to 3 cents a marble for a 3/4" flintie.
In the 1930's, Berry Pink had a big part in bringing marble prices way down.