Most good tire installers will only install studded tires on all four
wheels:  you don't want very different adhesion/traction characteristics
front to rear.
Second, unless you are going to be driving on hard ice a lot, YOU DON'T
NEED STUDS!! You lose traction on dry pavement, even asphalt, with
studs, and they tear up the highway surface something fierce (come drive
the freeways in western Washington if you don't believe me).  Studs are
an advantage on ice only, no help at all in the snow.  Perceived help in
the snow is because studs are normally installed on very aggressive snow
treads, the help is from the snow tires, not the studs.