> You'll not cover even S&H costs. $3-$5 is realistic, and yes, it was done when that made sense.
I wasn't counting shipping in the price, just the blank CD and whatever it costs to burn data onto it. Feel free to substitute a more realistic base cost; it's been a while since I priced blank CDs, and the overhead was no more than a guess. Including S&H, $3-$5 is well within the margin of error.
In the case you cited, as giraffedata pointed out, they really were a hardware & service vendor--they were paid for the CDs and the service of filling them with third-party software (plus S&H). No one would pay them for the software itself knowing that said software is available for free.
In short, if you're making a standard retail markup over the cost of manufacturing the discs, you're a hardware/service vendor. If you're making significantly more than that, then you're being paid for the data on the disc, not the disc itself, which makes you a software vendor.