The compressor I ordered for my SIL was $250. I was able to determine that a Tecumseh unit was a direct replacement and often used by Sub Zero.
I found a refrigeration guy to come in and remove compressor/evacuate system, flush the entire system, replace some type of inline filter and valve, install compressor and recharge. Took him about 4-5 hours. I sourced him through Craigslist (Wanted ad) and he only charged $250. A sub Zero tech will charge a minimum of $1500 around here.
Compressor: This is one place that was slightly higher in price:
Toll Free (800) 597-3022
Fx: (562) 468-0516
20234 State Rd.
Cerritos, CA 90703
kitchenparts@verizon.net
http://www.a1service.com
http://www.coldsupply.com
Tecumseh Compressor 1 259.99
#AE140AT-723-J7, (1/5 HP, R-12)
(replaces #AE140CT-184C4)
I can get the other place if needed.
BTW, her last compressor was replaced about 5 years ago.