Is this a good starter bike for $500. specialized secteur comp

Good starter bike: yes.
Good starter bike for $500: no.

Asking too much, imo. Looking at the condition of the derailleur and cable, it’s a safe bet that it’ll need to go straight to a mechanic as soon as you take it home.

Is that cassette even compatible with the drivetrain on this bike? It’s huge! Might explain why the chain is dropped.