Some guys gave me the idea to add donate button in mobile apps instead of adding ads. I search in google, but i couldn't find useful information. It seems that this is impossible for iPhone. There isn't information for BB and i found one discussion for Android. Do you have experience with such implementation? Is it possible? I have an idea to add link to web page(simplified for web) where i will place paypal donate button. What you think about this idea?
I can only comment on the iPhone side of things... At this time, they still don't seem to allow donations within the app, even via in-app purchases unless of course you make the in-app purchase into a feature upgrade or unlock some new content.
Updated info from Apple's app store guidelines:
21) Charities and contributions Apps that include the ability to make donations to recognized charitable organizations must be free The collection of donations must be done via a web site in Safari or an SMS
I'm planning on doing this in the future. You've just got to come up with a good idea for a reward!
As long as you give the user something in return, it should be approved by Apple (according to their own policy; You must deliver a digital good or service within your application. Do not use In App Purchase to sell real-world goods and services.
).
If there is a policy question, it would be a question of the policy of the application marketplace (such as android market) used to deliver the original application.
Android phones are not limited to a single source of applications, so you are not bound by the policies of the android market unless you choose to publish there.
On the technical front on android, you can display web pages in your app, send the web browser to urls, and do ordinary java-type or unix-type sockets network stuff, so you should be able to rig up something.
I have seen plenty of Android apps have paypal donations in their apps.