It's probably your starter. Have someone take a wooden spoon or a small hammer and lighly bang the starter as you try to start it. If that works, then you definitely need a new starter.
Yes, it's possible, but unlikely
I have the same problem on my 95 Sable LTS
It's possible a seal has broken. Find where it leaks from, could be pump, hose or steering ram. Then replace part.
Could be a bad inertia switch.
Could be sucking air into intake.
no not possible
it could be the fuel filter is pluged or the fuel pump is out
Depending on which engine you have, an alternator could range from $140-195 (USD) at Autozone.com.
In my 03 mercury sable, I had the same problem and it was the PVC elbow hose. It had a huge hole in it and I saw online that this is a problem with the 24V sable.
Check for codes(possible cam sensor), check fuel pressure bleed down(possible fuel pump).
have you checked the oil level in the transmission ? I'm betting the answer is no
Lack of or absence of maintenance such as oil changes and fluid levels.