The reason the tires are less expensive is that they have very few studs on them. The studs are in the centre of the tire also, so when you lean over for a turn, they are not gripping as much.
I am guessing a bit here, but when I studded my tires, I studded them on the side, so the studs only gripped when turning, which helps prevent the tremendous amount of drag studs can create.
Even with studs you have to drive slow. They help, but they are not miracle workers. Expect the worst.
This is not a lecture BTW, as I have been there myself. I've had a couple of crashes and one was at a fair speed, going straight, down a hill on solid thick ice, with a heavy backpack with a laptop in it, on a road bike with skinny treadless tires. The odds were stacked against me big time.
I zoned out thinking about something and zoned back in after I was barreling out of control, when suddenly I was on the ground, looking around, hoping no one had seen me
and trying to gracefully remount the bike, trying not to show myself hobbling with wounded hands.
I knew that if anyone saw me they would say; "see I told you driving in the winter is dangerous!" and they'd be absolutely right.