This happened to me yesterday on an LG. I called around and the running rate is $900. He gave me a $40 discount without the tax charges, if I paid cash or Zell. That was $114.25 less which I am so grateful.
It took the guy an hour but it seemed complicated. He had to use the torch to remove the compressor, compressorized the new unit to the required pressure, used the torch to put the new compressor in, changed the attached filter, and added freon. He said that LG purposely put a poor quality compressor in so that customers would have to buy the replacement after five years. I am just glad to get it fixed and it is much colder than before. Best, K.