The psychology behind how we spend our money is a wondrous thing. I’ll gladly throw down $1 a day for a Diet Coke, but I’m reluctant to spend $1.50 on a box of pasta that would feed my whole family when I can get it for less than that on another day. I’m also reluctant to pay for additional levels on my iPad games. I’ve done it once or twice, but it’s not an easy button push.
For whatever reason, mobile users will do almost anything to keep from paying for an upgrade – including engage with ads.