1996 Suzuki Sidekick AC compressor pulley to replace?

Air Conditioning problem
1996 Suzuki Sidekick 4 cyl Automatic 104214 miles

Hi,
I have found a '96 Suzuki Sidekick I wanna buy but the owner wrote me saying that there's a problem with the compressor pulley (it leaks) and for this reason the freon lasts only 2 days.
I have found the compressor for about $215 but I don't know how much mechanic charges for this job. I don't know if it is worthy to buy the car or not. Any suggestions? I copy what the owner said: "as far as the a/c I want to be completely honest. I put 2 cans of freon a while back and the a/c worked for about 2 days so it works, but the freon came out and I took it to an a/c shop and they checked it and told me it was leaking from the compresor pully so it leaks it pretty fast "
Thanks!