It is very important to find out whether the horn is in playable condition and whether it needs work.
Saxophones are surprisingly fragile and leaking pads make a horn hard to play.
Find out when it was last serviced.
And even a playable horn will probably benefit from a service, so budget for that.
It would be good if you could get a competent player to try it out for you.
Also it is a good idea to find out whether the horn feels right in your hands - sometimes an instrument feels good, and sometimes not. Even if you are a beginner, you can find out a lot by having a honk.