Known good ethernet card under $20

I'm gifting my old hackintosh to my wife. It works well, and is faster than her old Core2Duo hackintosh. It does have network problems that I never got around to solving: sometimes multicast just stops working (which essentially breaks file sharing and printing on the network), and more annoyingly, if a lot of data is uploaded, the machine eventually freezes up with warnings about some network queue overflowing. Reboot is the only recovery in that scenario.

This is using the built-in...

Known good ethernet card under $20