Growing up, my family had a series of early personal computers -- a Sinclair ZX81, a TI 99/4A, and even an early IBM Portable (which was not as portable as its name suggested). Today, let's talk about that Sinclair machine. The ZX81 was dirt cheap and extremely hard to type on, thanks to its membrane keyboard. But did I mention the dirt cheap part? Because of its price (in the US the Timex-produced variant was under $100 in the early 1980s), it was accessible to a very broad audience. It was also, if my memory is correct, a huge driver for people to get better personal computers with real keyboards. Typing a BASIC program into the Sinclair was possible, but it left the nascent programmer wanting more -- and that programmer often moved on to a fancier machine like an Apple, Commodore, or IBM computer. Many from that generation of early PC users (including myself and my brother) eventually went on to write software professionally.
Here's a video about Sir Clive Sinclair, the creator of the Sinclair personal computers, among other gadgets.
It should be noted (and indeed is noted briefly in this video) that Sinclair was just one among many early computer pioneers who brought "personal computers" into homes. But his computers were a huge deal, mainly because they were small and cheap -- in an age when even personal computers were large, heavy, and often crazy-expensive. Read more about Sir Clive Sinclair at Wikipedia.