I've had minimal luck at Staples. I've tried their self-serve, and it ALWAYS rescales it. I tried printing just a jpeg by itself, and it will only rescale. WHen I try and "print" it as a pdf then print the PDF, their self-serve machines completely remove all formatting options. Once the girl working there offered to just print my stuff for me at self-serve price, but the other two times the other person working said she wouldn't due to copyright.
I just go to the UPS store now for printing. $0.40 a sheet, never any headache (one of the girls working there always like seeing what I've got, and the guy there has a super mario tattoo, so they just don't give a shit about copyright)