Is it allowed by Google? And if so, do the paid ads have to be in compliance with how you would otherwise run Adsense ads, e.g. how many per page, per type?
Can I run 3 x 300x250 adsense spread in posts, then run a paid banner across the header? Adsense only allows 3 of these type of ads per page, but if a header and footer ad was privately paid, can the three adsense ads exist in the thread posts?