well..i dont know any monthly paying programs..but i have experience with a Pay per view ad network, actually its not an ad network, but an estore. they pays 0.01$ for each banner display and 100%...

Adsense, Yes the best PPC program over web you can get. But most of the blog users are disappointed with its strict policy to approve a blog! Am also!.They rejected my application 10times .Honestly...