The size of the board is a natural focus. The smaller the board the lower the cost. Part of the PCB size has become the standard, as long as the size of the cost to do so will naturally fall. The CustomPCB website has some information on standard sizes.
Using SMT will save money compared to THT because the parts on the PCB will be denser (and smaller).
On the other hand, if the parts on the board are very dense, then the wiring must also be finer, and the equipment used is relatively higher. While the use of materials should be more advanced in the wire design must also be more careful, so as not to cause power consumption will affect the circuit. The cost of these problems, comparable to reduce the size of the PCB to save even more.
The higher the number of layers, the higher the cost, but the smaller the number of PCB will usually cause the size of the increase.
Drilling takes time, so the fewer holes the better.
The buried vias are more expensive than the vias that penetrate all the layers. Because the buried hole must be drilled in the hole before the first hole.
The size of the hole on the board is determined by the diameter of the part pins. If the board has different types of pin parts, then because the machine can not use the same drill drill all the holes, the relatively more time-consuming, but also on behalf of the relative increase in manufacturing costs.