Banner exchange programs
You can use a banner exchange program to slowly increase the number of visitors to your site. They do not generate much traffic when you are just starting, but they help bringing in extra visitors when your site traffic starts to finally take off. To bring in a single new visitor you may have to display other people's banners to several hundreds of your existing visitors. If you don't have those visitors in the first place, joining a banner exchange will not help you.
Do to the low exchange rate of banner exchanges, I would only advice their use for promoting high-paying well-performing sales pages.