If you want to buy mobile advertising inventory cheaply, that’s easy enough to do.
People are vacuuming up mobile content to the point demand may forever be playing catch up to supply. That will definitely drive price down. It’s cheap because it’s plentiful.
The other reason things are inexpensive is because they’re poor quality.
Only one of those factors is a buyer’s advantage. If you’re buying mobile inventory really cheaply, maybe it’s worth asking who’s got the advantage.