I don't think throwing around prices is going to help much. A lot depends on how compact the board must be and how many interfaces need to be routed. A more compact board drives the layout time up exponentially. It also depends on how clever the designer is and how fast/easy to use the PCB package is he/she is using. If you plan ahead during the schematics stage (which means the component placement is done in parallel with the schematics) you can optimise a lot at the schematics stage and reduce the board layout time dramatically.