If you have local thrift shop like Goodwill or Salvation Army, try those. They often have working TVs for under $10.
I got a nice 9" CRT TV with AV ports for only $3 and it works, it sits next to soldering iron station for testing video games while it's being modded. Still looking for a decent bigger TV to replace my Commodore shit monitor. RGB display smaller than 30-something is extremely rare and I have never seen Sony PVM anywhere cheap. The drawback of living in USA is RGB display were poorly supported and expensive, then they wanted better and got HDMI which doesn't support RGB anyway.