If you do not introduce paid content, the price of the game is quite good. I think the prices do anything unnecessary for popularity, you do not have enough advertising. For example in the Russian internet market find you just not possible. And I doubt that on other Internet sites with your advertising business are better. And of course need access limitations of the demo, otherwise it is not clear why pay so much money if there are free products. After all, difference your game inside, outside can not see it. Do not judge strictly this is only my personal view of the problem.