OSH Park has been doing 4 layer boards for at $10 per square inch for a set of 3 for years. Shipping included. 2 layer for $5/sq in. Much cheaper for anything but the largest boards.
It was actually only recently that China low volume manufacturing beat out OSH Park for very small boards once you factored in shipping.
At one point recently, I used OSH Park to make a PCB that was exactly 1 square inch, and I felt like I was stealing money from someone with how cheap it was.
For the record, college was more than 3 years ago for me, and $33/board (last I checked) does not beat any of the other prototyping services except at very large sizes - they go up to 60 sq in for that price.
It was actually only recently that China low volume manufacturing beat out OSH Park for very small boards once you factored in shipping.