How do mobile apps monetize paid installs? (CPA networks)

Ok so I see that a lot of content lockers have offers that require installing a mobile app. When you install an app from an offer, the locker's owner gets paid (like in this picture).



Now, the solitaire offer has been running for a while now. I'm guessing that the app owners pay somewhere around ~$0.50 per install to the network (and network affiliates get $0.42). So this indicates that they are getting profit from these installs. How is this happening? Does it come purely from ads?

Cheers

Would like to know too, i'm curious about the cpa network side of profit.

Ive always assumed unlike other apps solitaire makes their profits purely through ads. If they get 1 user out of 5 who uses the app regularly they can expect about 0.10c perday from a single user.
I'm not that into app marketing so i'm not sure but they're obviously profitable.