if anyone is looking for a cheap entry-level oscilloscope to look at some diy video signals on - im recommending this ZEEWEII DSO154Pro 18M you can get for around 25euros…
Its very small and cute and has rechargablr battery and function generator and handles video signals surprisingly well for the price.
I wrote a little post about some oscilloscope options over on underscores also if you want to read more on the topic 
here it is inspecting some parts of composite video signal:
