I've never bought anything but used test equipment and my experience has been overwhelmingly positive.
If one wants a <$100 oscilloscope there is not much other option besides buying some kind of toy.
You are absolutely correct in terms of toys. My only concern with newcomers buying used equipment is whether, should it be non-functional or becomes non-functional in short order, can they fix it or afford to scrap it? We had one fellow on here who went through 2 junk scopes, a complete write-off on each before he moved on to something decent.
Some of the top name equipment can't be fixed due to proprietary components which are no longer available. This creates a tendency to buy a second unit hoping for parts to repair the first (or the other way around).
The alternative is also suboptimal, toys are useless.
And yet, for all my concerns, my purchases have been fine. I have had that Tek 485 for a very long time and it still works great! I don't use the bench meters very often but one of them came with current calibration. All have been excellent buys.
It's a risk and it probably can't be avoided. I guess I would give merit to 'recent calibration', I would obviously avoid 'for parts' and somewhere in the middle there is probably a workable unit. "Lights light up" doesn't give me a very good feeling. If I saw a trace on the screen, that would be helpful. Most used scopes don't come with probes so there is another cost. Not much, but just enough to be a surprise when you open the box.
It's just the way it is in the used equipment game.
Probably the least expensive of the credible scopes is the Siglent SDS1052DL+ at $259. 50 MHz, 2 Channel
That is a lot more than the OP wants to spend.
But it comes with probes and free shipping and that's worth something.