Search the archives here. There are plenty of threads on the subject. Responses always vary from sheet pricing, sheet pricing depending on files provided, complexity, and so on.
In our experience it can be nice when you have time and a nuisance when you dont and a lot of it will depend on whether your customers will be handing you a hand or computer drafted sketch than you then have to generate code from or if they are supplying you with files you are confident to work from directly (never the case for us).
In my world I have two main shops that I cut for periodically but they only supply drawings. No CAD, no .dxf's. So the entire job has to be input and then output to the machine. That adds to the per-sheet cost. If we had someone that could ship us .dxf's that we could quickly and easily toolpath it would be a different story.
The variables will mainly be dependant on the what your customer ships you and how standard/non-standard are their typical jobs.
Then, at least for us, you will have to overcome the delusion many of them will have at the onset with regards to your per-sheet price and drawing price as many of them will insist they can process the panels just as fast or faster/cheaper themselves (when they see the total price for XX sheets) as they are not accounting for ordering/receiving material, multiple ops and setups, packing, clean up, and precision parts.
Many that have contacted us are firmly in the fuzzy math category with regards to all the processes and ops that factor in to non-cnc panel processing.
Just my $0.02 Search bar is in the upper right corner, its your friend.