If I wanted a cheap iPhone I would hold out for Apple to drop the price of the 5S to $100. I think that it might already be the price in some places.
The 5S is a 2013 model.
The 5C is a slightly cheaper version of the iPhone 5, which is a 2012 model. I have the iPhone 5. My intent is to upgrade to one of the versions of the iPhone 6, but I might look at other brands too.