Just bought a regal

I just bought a 1996 buick regal with a 3800 engine with 170,000 miles on it. The body is pretty clean besides minor dings. It has a nice smooth ride it has a minor oil leak im trying to figure out now where its coming from and is gonna need a condensor and ac compressor.
I payed $300.00 for it.

How much life do you guys think it has left in it? and is it anyway to bypass the ac compressor with another pulley once it goes bad?

Is it anything I should look for or watch specifically with this car engine/transmission etc I don't know much about this engine or car.

Thanks