Clutch going quoted 3.5k for new one

[Subarusteve]

I'm new to this I bought a 04 Liberty wagon last week for a good price it has high ks but in really good nic,
The owner told me the clutch hadn't been replaced in 170000ks and that I would need a new one soon, it started slipping the other day so I rang up the Subaru dealer and he quoted me 3-3.5k for a new one??? That sounds pretty crazy.
Also my car has been idli g really low he told me it was because it was tuned by Sti dock lands 150000 ks ago and it just needed a tune up. I really love the car so any help would be great