It really depends what you are looking for (#channels, features, etc) but I can’t imagine a scope at that price worth much (unleas a friend is selling you their old one or something).

For the money, this is an awesome scope - (Siglent SDS1104X-E 100Mhz digital oscilloscope 4 channels $500):

https://www.amazon.com/Siglent-SDS1104X-oscilloscope-channels-standard/dp/B0771N1ZF9/ref=sr_1_3

I should follow up on my comment: it could be that a scopemeter provides all you are looking for. I don’t know what you are planning on using it for. To me, if someone needs a scope (vs just a multimeter) they should get a proper one with multiple channels, sampling speed, trigger features, etc. so they can handle whatever comes there way.

I agree that sub $100 is tough for a new one. I have a cheapy ($215) scope that is good enough for anything I've needed in pinball.
https://www.amazon.com/gp/product/B00RJPXB6Y

Older but top quality scopes are all over the place. Stick to Tektronix
and you can't go wrong. Have two here I'd be happy to sell you for $100
that would be fine for pinball. But shipping would be a bear. Look locally,
especially at ham radio groups as these guys (like me) always have extra
gear.

There are tiny chinese made scopes pretty cheap but you'd be better
with a Tek by far.

See if your neighbor has one and steal his. Just don't get caught, otherwise more than $100. Don't ask how I know...

Seriously, I have a Hantek DSO5102P. Dual channel scope and it was about $225. Works for what I needed it for.

dso-5102p-a (resized).jpg

At a minimum, I would say more than one channel and good trigger features. Being that at this point it sounds like you don’t have much experience with them, is it possible for you to rent one or borrow one to learn more before spending too much? If you aren’t going to use it often, it may become an expensive unused tool... a very cool one, but still unused.

I got this for $146. It won’t do high-speed digital but for pinball and early generation computers I think it will do what you need.

C514C4B3-FCD1-4742-A785-4E58A42F1492 (resized).jpeg

It comes with two probes and is a snap to use. It also has a lithium ion battery Making it good for field repairs.