Link exchanges with other arcades works well for me. There is also http://www.funpageexchange.com/
I have used them and I got a lot of bang for the buck. There are also a number of arcade topsites around and plenty of banner exchanges.
If you do not want to spend money to get people to the website then what is the point of having the website? People do not just go to the website.... how would they even know about it in the first place?