You download the channel in the Wii Shop channel for 500 Wii points.
You can buy points in stores for £15, you get 2000.
You do not need an online game to go onto the internet channel, just internet acess (router, wifi stick etc)
Its not really all that much money, you can get a game for circa £30 has has a finite end, or a browser for about £5 and the internet is forever changing