How can i create freemium feature in game for android or ios

Hi,
I just try so many game engines like Game salad,Unity 3d , Stencyl , Game maker (they are very hard to use but GS and GM is easy) but now i am using construct 2 and i found this one easy and effective . Now i make my first game using construct 2 . I want to open my Developer account in play store and I tunes . So i got an idea why not i publish my app on my own blogs and make the money for account .
But now i am confused . I check most freemium games like Jet pack Joyride (pay for Coins and Items)
, Candy Crush and more they makes money . I don't like ad revenues for my game .
I want to make a coin currency in my account to buy them with cash or get by play game similar to jet pack joy ride . But i even don't know what they use to collect money or how users spent money . Which method is is used by Halfbrick to get the money who's spent by users and does they use credit card or mobile sim balance . If they use any website to get the money or anything please tell me.
Can anyone please describe properly how can it makes money from debit or credit card or mobile balance or a website where the connection between users and me (They spent money for items and balance deposit to website there i can withdraw ) is there anything or different or how users pay me what i have to submit in my game a website or a link . I just only want to make developer account in Play store or I tunes .
Thanks , Please Share your words .