If you must go cheap, or just can't afford it (i fall into both of these categories) you can try for the Innova studded tires. They are cheap tires that have mixed reviews. Generally, people aren't saying that they do not work, they are just saying that the stainless steal studs (rather then Carbide) wear down too fast.

Seems that you'll be lucky to get one season out of them rather then the usual 3-4 seasons out of Nokians/Swalbe studded tires. Here is a good thread i found on the Innova tires.

http://www.bikeforums.net/archive/in.../t-268951.html

I just got myself a pair of Innova 700x35c so heres hoping for one full season of grinding down metal