1 – There is no real “typical” cost, because it depends on the length and how much graphic work you need done. I would say, if it is less than 20 pages, it would be less than $400-500 or so though? It also depends on what country the designer is from, because some countries have lower standards of living, and you might be able to get the work done for $200-300 if the designer feels it is a good price for the amount of work.
2 – Yes, it is usually a PDF file, and it is easily readable on phones most of the time. Just make sure you test that out while designing it.