I picked up a Denso compressor from Rockauto, a drier and expansion valve from Ebay. The compressor was $200 but the drier and expansion valve were $9 and $7 respectively. All the parts came with o-rings.
Changing the compressor is easy and most come pre-oiled. But, getting the expansion valve out was a PITA. I think I either watched a video or found pictures online on how to remove the evaporator coil and expansion valve. Verify that your high and low shrader valves on the compressor are not sticking out too far and causing a leak.
Once the new parts are in, I borrowed a vacuum and manifold gauge set and started pulling vacuum. Pull vacuum close to 30. BTW, you know the vacuum is working because it will be loud. Once it pulls full vacuum the noises will lessen. Shut off the vacuum, confirm the gauge reading, and walk away for 30 minutes. If the manifold gauge reads the same, you are golden and ready to add refrigerant.
BTW, examine the AC belt while you are at it and verify proper tension.