Aftermarket Magnetron

This is a great site, glad I found it! I love the detailed instructions on how to replace the torsion springs on the microwave door. I hate the fact that I keep having to use those instructions. There should be a class-action. I now probably have to replace my magnetron on my Kitchen Aid (Whirlpool) KEMS308GSS2 unit (AP part # AP3010033). I saw comments on other posts mentioning aftermarket parts. Does anyone know if there is a less expensive aftermarket magnetron for this unit? Is there a way on this site to search for aftermarket parts? Thanks in advance!