Price is heavily dependent on how many PCBs of the same type you want printed and if you need assembly or are planning on it doing it yourself and will be sourcing the components from the cheapest possible suppliers.
Shipping from the Asian shops also has to be factored in, any sort of rush printing or shipping gets very expensive.
Ive paid £40 each for a run of three 40% PCBs fully assembled/tested and with priority shipping that was less than a week. This isn't actually that bad when you compare to a similar sized PCB from a store in the US for me in the UK when adding on the shipping and potential customs fees.
Cheapest possible will be the free PCB option from PCBWay, but you will need to do some work to get that money back from them https://www.pcbway.com/free_pcb.aspx