Having sponsored ads like Google Adsense or Yahoo Publisher Network Ads on the same pages you are selling products is not a great idea.  Think about it - What if you have a product that will make you 400$ profit and someone click on a similar ad on your page that is only going to make you 75 cents?  See the problem?

There is a good chance that you could lose alot of revenue from having these kind of ads on a dropshipping site.  I know it can seem tempting cause of all yo may have heard about sponsored ads etc. but be very cautious of how you really try to make money with them.  If you have several information pages on your site (just for content) and you are not selling products on them, then that may be a great place to have the ads.  

I try to avoid sponsored ads all together on sites selling dropshipping products because I feel it really takes away from the integrity of the site.  You want to make your visitors as comfortable, and safe as possible on your site in order to get them to give you a credit card number.  Having a "spam-sensed" looking site can be a draw-back.