Where is going to be the cheapest/best place to get: Decent mudflaps (Rally Armors look nice...) and even as much fun as I am having sliding around on shagged all seasons - Snow Tires.....
Search for mudflaps on nasioc in vendors section and for tires go on to like edgeracing or tirerack print out the price and bring it to discount tire they will match it.
I have the Hankook Winter iPike. Great winter tire for the price. Can be had from Discount Tire for about $100.
What size wheels? If you have 16" or smaller and want some good, lower priced snows look into the Winterforce snow tires at either Firestone or Tires Plus. Ridgedale Firestone always hooks me up good.