You don't HAVE to talk to telecom providers - you can use Pay-by-SMS services like Zaypay (http://www.zaypay.com).

If you plan on offering the application via the iTunes App Store or Google Play, then you can have them sign in and purchase "credits" via in-app purchases. This way, they can use iTunes gift cards. Plus, which teenager doesn't have iTunes credit?

Edit: In the case of Pay-by-SMS, the parents would find out either way when they see the bill. So, they might as well just use their (the parents') credit cards instead of allowing the teenager to charge it to the monthly phone bill. In this case (and other cases where the parent(s) are aware of and approve the service), you might just want to include credit card payments (via Stripe).

I despise Paypal, but you can always try that.

And because you pay them a commission for each sale, you're not losing money if you offer these options and they aren't used.

Edit 2: Zaypay IS AVAILABLE in Argentina (http://www.zaypay.com/outpayment).

Thanks, something like Zaypay was what I was looking for :)

It sounds like you'll have a tough time getting your customers to pay you - if you're after money, is the idea still worth pursuing if you're going to have to 1) convince them it's worth paying for, and then 2) find a way for them to pay you? It seems like a lot of hassle.

That being said - people who don't have credit cards a lot of the time have parents/guardians who do. You could try that?

We are doing research yet, but we got 1 resolved we think (I mean, people will want to pay for it). Number 2 is what our trouble. This is not in US, but Argentina, where people are not used to give their credit card details online, and they won't definitely do it for they childrens.

It sounds like you've picked an idea that will be very, very tough to make a sustainable business out of.

Use cellphones. Usually when there is a natural disaster or other catastrophes, the red cross has a way to text in a word to number and then they charge it to the phone bill at the end of the month. I do believe though that this method is only good for donations and not businesses but hey, maybe you can prove me wrong?

Teenagers will find a way to buy stuff if the want it bad enough. Find a way to make the product really attractive and they will find a way to buy it. What type of product is it? By the way, if there is one segment who will find a way to pay for something its teenagers.