The cheapest mechanism was paper. The storage method was printing it out. The entry method was typing it in. This is a tried and true technique that flourished into the 90s and is arguably still used today, save it's now known better as "cut and paste".
Most every type of mechanic was used in the past to widely distribute software and data, paper was the dominant form. I can hold any number of thousands of magazines that relied on this mechanism for wide distribution.
Other mechanisms were also tried. Bundled tape cassettes, bundled records like vinyl records, only flexible to survive shipping. For a short period there was a bar code style scanner that you could buy and read source code from magazines like Dr. Dobbs. But the device was at least $100 to purchase, and it didn't last long. There were also radio broadcasts of software, but those required cassette interfaces. Inevitably, of course, this evolved in to CD-ROMs.
Remember 101 BASIC Games? How was that distributed? And how popular was it?
A paper card reader is extremely expensive. A paper tape reader is also expensive. To quote the lawyer Gennaro from Jurassic Park: "Is it heavy? Then it's expensive."
Paper is cheap. Really cheap.
BASIC, FORTRAN, LISP, assembly, Forth, HEX DUMPS, all of these have been shared via print to be coded in by the user. I distinctly recall typing in, twice, with a friend, an extensive hex dump of a Life program for the PET. It never worked, either time, and we were pretty thorough that we got the codes right. So I don't think it was us.
Later, magazines would introduce programs (which were typed in) that let users type in code and added checksum and other verification techniques to better ensure error free transfer of the data.
So. If you want cheap, the printer is over there. If you want really cheap, here's a pencil. Is it efficient? It was efficient enough to be the primary mechanic for a wide range of enthusiasts for 10-15 years. So, it's got that going for it.