Actually, the Raspberry Pi that they recommend is $90. You could accomplish the same thing (anon middle box) with a much cheaper router. If you look at the Github page for PORTAL: https://github.com/grugq/portal It lists some recommended routers that are in the $20-$50 range. Other advantage may include that it's easier to setup and probably more secure. thegrugq is highly respected in security circles. You should prefer solutions that are made by people who know what they are doing.