I found a rather interesting video on YouTube about building your own iPhone; Originally I thought this was going to be a knock-off, lookie likey type phone, but no, this was the process of buying all the components and putting it together yourself rather than going to an Apple store and buying one in a box, but to build a real working iPhone.
It was certainly interesting to watch someone go through the process and in theory saving himself some money, not sure how much exactly, but it was a goal he set out to do.
His task was made simpler by doing his project in Shenzhen in China, were all those back street stalls and markets sell almost anything.
Video Link: https://youtu.be/leFuF-zoVzA
The Answer to the Cost link: https://youtu.be/-KucQDXnKws