You should not assume that the price you see online will apply to the actual compressor. Shops mark the parts up and there are also peripheral issues such as a new accumulator, new orifice tube, flushing the system, and so on. Reman compressors around here are around 200 bucks on average and an accumulator is about 30 or so. That is sans markup and the reman compressors are Four Seasons. I’ve had issues with Four Seasons remans and refuse to use them.
Some shops are hesitant to use customer provided parts and if they do there may be zero warranty on any work done.
If leak checks reveal problems in the system other than the compressor that would be additional cost.