From personal experience I remember that majority of kids had these here in Poland in the end of 90s and early 2000s but the quality of
tama egg as we called these (not knowing it was a tautology), varied. Some richer kids had the original tamagotchi while most of us got bootleg devices sold on the market by merchants from Ukraine (who also were selling bootleg copies of SNES along with cartridges - majority of these were "9999 in One" games, sometimes even taking shape of original Playstation) or in newspaper, toy stores. Bootleg copies weren't lasting long - the common issue was with ZEBRA connectors on LCD that were prone to failing if device was dropped and that happen a lot. I had luck to find some Bandai branded tamagotchi but now I doubt it was original - I did tried to look for any info about it but no luck.
Despite if it was original or not, we had fun - two classmates were really happy about their 28 in 1 type of devices, where they both pick gray aliens. Later on I had some bootleg 8 in 1 device that I really liked. We also were wearing these on ribbons around neck instead of pockets, since devices had a clock feature.
Edit: forgot to mention that there were also dating-sim tamagotchi-like device [1], not sure but probably aiming at teenagers/adults and one that had a more "natural" looking pictures of baby/kid [2]
[1] - https://3.bp.blogspot.com/-W8DZLytNPQw/Ujv5_PYCoUI/AAAAAAAAC...
[2] - https://orig10.deviantart.net/e9bc/f/2017/221/7/f/babybye2_e...