Android Guys have a series of articles that is very informative, named "40 Android Business Models"
In the beginning I thought it was just another run of the mill 40 things you could do with something or the other but after reading the part one, at leaset on was attractive to me;
Model #6: Make the App, Sell the App to Service ProvidersMay be create it so that it is easier to connect with Free SIP Service / account Providers. Yep
Some apps are tailor-made for the same strategy as Model #5, but targeting service providers rather than content providers. A great example would be a SIP client. SIP is generally interoperable, but it frequently requires lots of finicky settings that are provider-specific. Rather than (or in addition to) creating a SIP client to sell to end users, make it brandable for a SIP provider, plus have the means of “baking in” various provider-specific settings at the same time. You license the tailored app to the SIP provider, who in turn distributes it to their customers (probably for free, banking on more SIP minutes sold). Once again, you can leverage a single app into multiple significant sales, rather than having to only deal with end users.
So I continued to part two and ended up at part three. There were many good business models and a few suited what we do! If you are a Android Developer, (Any other developer for that matter,) it is a good read.
The link below is for 40 Android Business Models Part one, scroll down the article to find links to Part two and so forth.