It's been rumored for a while now that Apple will be releasing a lower-cost iPhone at some point this year -- most likely sometime in the fall, which now begs the question of how many of these low-cost iPhones will sell. Since they'll be cheaper than a regular iPhone, it makes sense that Apple will sell a ton of these, and analysts agree.
According to Piper Jaffray analyst Gene Munster, Apple is projected to sell a whopping 75 million low-cost iPhones in 2014. That's quite the figure, and it would blow the iPhone 5 out of the water as far as sales go, which would be impressive considering that the iPhone 5 was said to be the top-selling smartphone during Q4 2012.
Apple sold 47.8 million iPhones during Q4 2012 alone, but that included both the iPhone 5 and iPhone 4S. That's just for a single quarter, so sales for the iPhone were much greater if you count all of 2012, so 75 million seems like a reasonable number for a low-cost iPhone, which would average out to just under 19 million units sold per quarter.
Of course, a low-cost iPhone would cannibalize the company's regular iPhone, but it would still allow Apple to gain market share, especially in the low-cost smartphone market. However, I don't think Apple is too worried about cannibalization, especially after the fact that CEO Tim Cook mentioned it during the company's Q1 2013 financial earnings call.