Bidadvertiser

Bidadvertiser is another one of the best alternatives for AdSense. Advertisers bid against each other directly on your ad space. One of the Good about Bidadvertiser is they accepts all sites, including flash sites, sites with little content and password-protected pages.

Sign up is pretty easy and they would accept you within a day max. They are one of few PPC networks who pay publishers by Paypal. Since advertisers bid against each other for your ad space at beginning you might notice very low earings but You will see a constant improvement in your bidding over time.