Today when you buy a computer, it has just about every interface that most people would need. But in the 1980s, you needed some sort of interface add-on for just about everything. Want a printer? Make sure you get the right interface. A modem? Might need an additional interface for that too. Then there were all those non-standard RAM expansions...
In this ad from the June 1984 issue of Commander magazine, you can see just a few of the multitude of hardware expansions available for Commodore 8-bit computers. For example, for the VIC-20 you could get ~27K of memory for only $80! Then there were more obscure things like a cartridge switcher for the Commodore 64.
Then there are those printers. I can't believe how much a printer used to cost. What is essentially a typewriter modified to work automatically with a computer cost $600 to $700. If you wanted something designed from the ground up to be a printer and that could print at more than a few characters per second, expect to spend more.
I am not at all familiar with Apropos Technology but there were probably thousands of small hardware and software dealers like this one advertising in magazines throughout the 1980s. Most of them didn't last very long.
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