There were also smaller discs sold to be played at 45 rpm, called “45s,” which usually had only one song per side. If memory serves correctly, they used to cost about a dollar each, while the larger LPs used to cost $5 or $6.
I have more than 300 LPs and maybe 30 or so 45s.
Things stayed the same from the mid-1960s to the early 1980s when music reproduction technology changed again, to the so-called 8-track tape cartridge. The 8-track player would not play vinyl disc records of 33, 45 or 78 rpms. Soon, however, the 8-track was replaced by the smaller compact cassette, about the size of a deck of cards, but thinner. Remember them? The compact tape cassette could not be played on the 8-track machine and vice versa. Of course, neither one could be played on an LP record turntable. Planned obsolescence strikes again.
I have a few of the small, pocket-sized compact cassette tapes somewhere. They are easy to play while riding down the road, but the tapes wear out or stretch after a while. I also had a compact cassette player wired into my stereo outfit at home, with a corresponding increase in the number of wires in the back.
Back to the LPs for a moment. Whether on a stereo or a hi-fi (high-fidelity) system, you needed a turntable. Some came with a built-in amplifier (“amp”) and speakers. Others needed a separately-purchased “amp” and speakers.