The Samsung Galaxy S5 costs about $650 and sold 11 million within the first month. Not sure how much the iPhone 5s cost at first, and I couldn't find any sales stats for the first month of sales, but I'm pretty sure that's around the same price, if not, more than the 5s.
Galaxy phones are usually about the same price as iPhones, or more if I'm not mistaken, and have much more to offer + better specs.
Bigger screen, better camera, microSD storage if needed (I definitely needed it), and much more, so you're really getting more for your money when you buy a Galaxy as opposed to an iPhone.
In my personal opinion, Androids are much better than iPhones. I hate iOS, it limits you to basically everything you can think of, while the Play Store has an entire category for phone customizations. Even if you don't like customizing your phone, it's always nice to have the option available if ever needed. And many other things besides customizations and whatnot.