My first (owned) computer was a ZX Spectrum 48K.
That computer has a Z80A 8Bit CPU running at 3.5MHz. Technically, the Z80 has a 16 bit memory bus, so it can address 64Kb. The first 16Kb were occupied by the ROM (BASIC interpreter included), from 0x0000 to 0x3FFF. The remaining 48K (starting at 0x4000) were RAM, of which the first 6K are mapped onto the display area. Writing values in that area make pixels in the screen to turn on / off (bitwise). Loading / saving data was done thought the cassette and took long 4/5 minutes to start playing a game. I think this was very didactic.
This computer was very successful in the 80’s in the UK and Spain and it had some clones in Russia, Brazil, etc. It became very popular mainly for its affordable price and possibilities (color, hackability, game catalog, etc). Like most microcomputers of their time, it came with an integrated BASIC interpreter. You just turn it on and the BASIC was there waiting for you to type orders directly (REPL) or to type an entire program (nowadays starting a programming environment is not that simple). Despite its limitations (which were overcome with creativity by game programmers) its game catalog was rather large and it was another selling point.
Currently there’s still an active community and still electronic hacks are being created. Even a Kickstarted ZX Spectrum Next is out there (it’s a modern FPGA machine with some backwad-compatibility with the original machine, but not an original one).
The most recent exciting thing was seeing the speccy in Netflix Bandersnatch movie (check its easter eggs )