Macintosh Performa 550 Networking

I'm about to recieve a Macintosh Performa 550 for free. It doesn't have an ethernet adapter in it, but it does support one. Now I probably won't be running anything past MacOS 7.5.5 and most definately won't be running anything past MacOS 8.1. The only ethernet adapter I could find for it cost $59, now for that price I'll dial up with a 28.8 that I already have rather than cable modem, because that whole computer isn't worth $59. But I thought it would be cool if I could make it have internet faster than it could process.
This is kind of a long shot here, but does anyone know of anywhere that sells an ethernet card or such that would work in this for less than $60?

Maybe you can find a used
Sonnet Presto Plus (http://www.sonnettech.com/product/presto_plus.html) somewhere..