I also second the vote for the HomePlug standard as an alternative. I've been successfully using the a couple to provide network connectivity to my server rack in the garage. It they've proved much more reliable then the spotty WiFi coverage I could obtain.
There's plenty on
Ebay of both the original 14Mbs and 85Mbs HomePlug systems.
Although with all these things take the theoretical bandwidth given with a large pinch of salt. Quality of wiring, distance etc all have their parts to play. If you want to stream any Video or VoIP streams reliably then look at the HomePlug Turbo 200Mbs range of devices.