Printing business cards

If I have a photograph on a business card created in Illustrator, how do I know if the print shop can print it in "4 color process" or "2 color process"? What is "Spot PMS color"? Is that the same as "2 color process"?

Is there a price difference between all these including "just black and white"? I would think there is a price difference, but how the online print shops all display one single price and did not ask me whether I want 4 or 2 color or b/w or whether I have a photo in my design or not?