There are many ways in which the PCB cost can be reduced following good design practices. Below, some of them are shown.
If you need a standard electronic circuit, for DC or low frequencies and you do not expect too much power dissipation, use typical rigid FR4 substrates since you will reduce extensively the cost with respect flexible or high frequencies substrates or that include aluminium plates.
Do not use an expensive finish that you do not need, for example gold finishings can seem the best ones, but typically are expensive and for solder purposes are not always the best option.
Whenever is possible use one or two since it will simplify the process. When more layers are required to do the signals connection, different boards have to be connected increasing the price. The higher the number of layer the higher the increment of the price.
If you have to use multilayer PCB stack-ups you have the possibility to use through holes that can be done at the end of the process over the final stack-up. However, if you use blind or buried via holes the procedures are more complex and them more expensive.
Since more tools will be required, the price will be increased. Also try to not use very small or big via holes to help you to save money.
The shape of the boards can get expensive your panel because of the difficulty of the cut. Typically, the cut out is done using drilling processes, but if the shape is too much complex, lasering can be the only option, increasing in this way the prices, and not all always is possible.
If it is not necessary, avoid to reduce the width of the lines or the space between tracks to reduce the complexity of the process and save money.
Whenever is possible, try to do as much copies as possible, since many times, the preparing costs are the part that more is influencing the price. Sometimes to do one copy will have a close price than 10-20 copies, especially when cheap substrates are used. The price also can be increased if you have many different designs in each panel due to the longer required inspection time.
In the next post you will find information about how to optimize cost when assembling PCBs.