When launching a website you need to figure out just how you will market it.  First is your website selling a product or service, or is it relying on traffic in order to attract advertisers itself?  Should you buy website traffic or use SEO to get free traffic only?  If you notice good profits from the free traffic you are receiving, then it is recommended to try buying some traffic on a test basis.  Set up a campaign and track its results.  If what you pay and the value on the time spent to set the campaign up is less then the revenue you are receiving from the campaign, than double, triple, or quadruple your budget on the given purchased traffic.