[Mondial]

You really don't need the latest and greatest scope, but it should be modern enough that you don't have another restoration project before you can use it properly. I would suggest at least 20 Mhz bandwidth for typical troubleshooting.

Personally, I am partial to the Tektronix scopes built in the 70's and 80's. They are new enough not to need major restoration, yet sometimes can be gotten for less than $100 in good working condition.

The test probes for modern scopes typically have a BNC coax connector to plug into the scope. Some are available with 10X attenuators to look at higher voltage signals without loading down the circuits under test. Inexpensive ones are available for less than $10 on ebay.

I don't know what sort of scopes you are seeing on Facebook, but you might post pictures of a few so we can see what is available to you locally. The seller should be able to show you that it is operational and can produce a sharp clean trace or waveform before you consider buying.