I got some good prices for some Hancook winter tyres last year. I didn't get them in the end (bad idea as it turned out!). It is cheaper to get winter tyres with larger profiles, so you might want to get some steel wheels to go with the tyres, that way you don't risk damaging your nice alloys with all the grit and salt that they (should!) put on the roads during the winter months.
The hancooks were about £35 per tyre or something, wheels were about £20 each, all prices from my local stealership parts department!
Michelin have just made some new winter tyres. They are getting good write ups at the moment.
Its ok paying £35 a tyre at the time. Think about it, it should be the thing you spend loads of money on as its the only thing between the car and the road.