Humm .. i think this is a tricky question.
While it will definitely be cheaper to develop an application for android, the question you might want to ask (depending on what you want to do) is what is the ROI of an Android application versus and IOS application.
And even then, depending on the type of application & the demographic your app will be targeting (not to mention usability, design, general app quality) the response will likely vary quite a bit too.
But globally yeah, it's cheaper and less a hassle to make an android app i'd say. ..then again, i have an allergy to apples, and this is an android forum after all