You could get away with just one studded tire on the front,if cost is that much of an issue. Remember,you only run studs in the snow,so you're not going to wear through them as often as regular tires. My studded tires are several years old.

When I first started commuting,it was winter,and my first few snow rides were on regular tires. Studs/knobbies help alot,but regular tires are doable as long as you're careful. It would also help to run Kool Stop Salmon pads on at least your front brakes.

I wouldn't recommend this. First,if you get a flat,you have to cut all those zip ties to remove the tire. Second,plastic zip ties aren't going to come anywhere close to steel or carbide studs in traction.