Hello everyone, made it back to civilization again. Now to your question.
Assuming he is an experienced framer, you will be there to help so there are two of you, all stud and header lumber is on site, all trusses are premade and on site, he has a 16p air nailer, and you are only dealing with 4 exterior walls, then you should be able to frame it up in a day. Allow time for bracing and drilling holes in the base plates.
Assuming you have all exterior sheating on site, allow a day or more to sheet it. Allow another day or more to shingle it.
$15 is a bargain for an experienced carpenter. A good one around here starts at $25. Laborers start at $9 to $10 an hour plus social security, etc. I can find some experienced construction laborers (not sure I'd call them carpenters) down at a local bar who are between jobs and pay $10 to $12 an hour for temporary help.
Figure taking longer for one guy by himself. One guy can do it, but it goes much faster having help and helping raise the walls and trusses, make cuts, hand up boards, and do general gopher work. It never fails that you come up needing something and someone has to run to the lumber yard. If you help, you'll learn something and get a sense of accomplishment out of it. Good luck.
Post back and let us know how it goes. Also, the expensive part is the concrete. I don't here any complaints there. What is he charging?