Just some thoughts for the newbies:
A good low cost working second hand Tek analog scope is a joy, but a malfunctioning one [ worse if its transient or glitchy rather than clearcut] can be challenging to repair without good electronics skills particularly around high [ potentially lethal] voltages. 1990s+ scopes increasingly have custom parts that are hard to find; you may have to bid later on another model to use for parts.
Even if a scope was tested and working at the time of the sale, it could fail anytime.
What you'll risk is the unknown of the above during the time of purchase, if you win you'll get a scope for typically between $100-300, focusing on 100-400 MHz, 2-4 channels as is available.
New 20 MHz dual channel China-branded DSO are typically $200-$300 ; $400 for a 50 MHz Rigol 1052e hackable to 100 MHz. Even if Chinese label, some brands have been examined and discussed in other forums as being fairly good, so you may want to check them out via google for the skinny on Owon, Hantek, Rigol, & Atten. There is a lower cost line for Instek, a reputable Taiwanese brand that can serve you well.
The feature sets on low end DSO are fairly similar, but the single biggest difference is in real time sampling rate. A simple rule is sampling rate/10 ~ true bandwidth, don't just use the analog bandwidth or the 'repetitive signal sampling rate' as a measure as they are both limited by the real time sampling rate.
Good luck!