The network adaptor (now) is $40, but other than that the games are exactly the same price. All you need is the adaptor, your PS2, an internet connection, and a game.
to me online because i like taling to real people instead of cpus which is kinda boring but in mmorps like star wars galaxies and final fantasy xi and matrix online are good games so are fifa 2004 2005 and socom 1 and 2 are my best games i actually pay for swg but mn and ffxi i dont