In the Lobby, you can determine the currency of a Contest by looking under the Type column. Ownersbucks contest will display a blue OwnersBucks icon, whereas real money contest will display a dollar sign ($).
You can also filter contests between real-money and OwnersBucks.
In the top left corner of the 'Lobby' page. The filters are located under the 'Type' header.
Go to your 'Lobby" page
Tap the drop-down located under the different Sports.
Then Tap on the Blue OwnersBucks Icon or the Dolla Sign ($) to filter between the two types of contests.