network adapter for Toshiba RSTX20?

I have an old Toshiba RSTX20 that I reactivated for use in my guest bedroom. I previously had an old Belkin USB/wired ethernet adapter on it, but I can no longer find it and, of course, Belkin hasn't made that for years. The Tivo-branded wireless NICs are ludicrously expensive. Does anyone know of an inexpensive wired or wireless NIC that will work with Series 2/Toshiba RSTX20 Tivos?