If you're just testing the waters, an inventory marketplace like BuySellAds.com might be worth checking out. You can browse through the inventory of similar si

If you're just testing the waters, an inventory marketplace like BuySellAds.com might be worth checking out. You can browse through the inventory of similar sites to get a gauge of what you can expect, CPM wise: https://buysellads.com/buy/allsites/ https://buysellads.com/buy/allsites/ Later on, you might just want to strike one-off deals with interested advertisers, or build in a more "native" ad solution into your platform, etc.