Question about failing turbo

[jakelauer]

Hi, all. I'm a complete Supra noob (pretty much a car noob in general, actually). But I came across a 1990 Supra Turbo for sale on Craigslist. The post mentions this: Turbo Charger is going out but still runs.

My questions are:

• What exactly does this mean (i.e. what needs to be replaced)?
• Is the turbo charger necessary for the car to run, or can it work if the turbo charger completely goes out?
• How much would it cost to fix?

Thanks!