Alright, this is not a dish that really makes the rounds outside of my family. But I loved it as a kid, and it's much tastier than it sounds.
1 lb crabmeat or imitation crabmeat
1 teaspoon horseradish
1/2 cup mayo
2 teaspoons ketchup
1/2 cup milk
2 tablespoons flour
salt and pepper
Mix together, pour into greased 8x8 casserole dish. Add mixture of grated cheddar cheese and bread crumbs over the top. Bake at 350 for 1 hour.
Cost: depends on whether you're using real or imitation crabmeat, although imitation works just fine for this recipe. Let's say $4 for that; the other ingredients might set you back $1.50, depending on how much cheese you put on top.