Whats a fair price for online gameing?

Online gameing can cost from 10 to almost 50 dollars a month depending on the game. even though you probably spent 30-40 dollars just buying the software.A slightly higher price per month for games that allow you to download game clients straight from them so no software purchase is neccesary i think may be acceptable. But really im just curious to find out what an average gamer thinks is a fair monthly subscription price.Personally i think anymore than $15 a month is pushing it regardless of the game. Not saying they are overpriced just curious as to what others think is fair :)