My third printer, I paid $70 for, used (ender 3 pro return). It was missing several small components, one big part (top aluminum extrusion) that required some machining with a drill press, and had a bad thermistor.
I don’t think you can get a beginning printer for $100 unfortunately. Sovol and Anycubic make printers among the cheapest that are more beginner friendly (I think) than Ender, for roughly the same price. I have a friend with a Creality and an Anycubic Vyper, and the Vyper seems to be more beginner-friendly. I have two Crealitys and I love them, but both required a ton of modifications to become reliable.
Can you check your area for a local maker space? My local library has 3D printers for anyone under 18. Universities typically have a few of different technologies (SLS, SLA, FDM)
Look at Sovol or Anycubic in that price range. I don’t have direct experience with either. A good friend of mine had two Anycubics at one point last year and he said they were easier than his Creality.