I've found you can get the same apps to show up again but the more you download the less frequent they show up. Also, the more often they are for 25 (or even 5! Yeah, get tons of those) coins. So you can eventually get enough for one intensity set or UCP a week but not much more and sometimes not worth the trouble just to pull your hundreth rare.
When you download a trial game for mobacoins you have to play until it asks you to sign in to your moba account. Once you sign in, that triggers the mobacoin gift to your account. After that you can delete the game off of your device.
I stopped getting them 2 weeks ago. Have other people stopped getting offers? I was getting 100 coins a day for weeks and then it just stopped completely. Their customer service says nothing has changed.
Yesterday, I got a trial offer when the game started and it didn't offer coins. I don't mind it when they offer some sort of compensation, but it's going to be super annoying if they start bombarding me with terrible game pitches without anything in return.
I took a survey emailed to me from Mobage stating that I would receive 200 Moba coins within 5 days of taking the survey... it's been 2 weeks and still no chedda. Mobage if you're listening, I lied on the survey anyways.