Prototype PCB manufacturers
Here I list some of the "cheap" PCB suppliers I have come across.
Remember the prices posted here are taken from the webpage, may be misleading outdated and there products are not entirely the same.
US based, $50 for a double sided PCB.
Bulgaria based, $33 for double sided, $26 for a single sided PCB.
UK based, £30 for a double sided PCB.