Check out the Coop & Run forum here on BYC........lots of ideas there! Remember that chickens deal with the cold relatively well, but the humidity created in a coop that is too tight will cause frostbite and respiratory issues. Ventilation is very important.
For materials, check out any tractor, ATV, RV, mower dealers and ask for plywood crates they may have. Lowes, Home Depot, Menards, etc have a "seconds" section that may have enough of a material for a small project, ask where the place in their store is (our Menards has it outside). Some Habitat for Humanity locations have resale stores that sell donated building supplies at reasonable prices. Garage sales, especially those out in the country, can have great finds. I got three 4x8 sheets of 3/4 plywood that had green camo spray paint that was part of a deer stand that new owners took down. Many people would be happy to have you take fence panels that they are removing or replacing or chain link dog kennel panels, don't be afraid to ask for them.
I can't help on the silkies.....I know there is at least on BYCer, tbitt, that has some and she lives between you and me. Maybe she will chime in on how they are dealing with the cold and if she has to do anything to accommodate them. The broodiness of them is much heralded so they may not be the best choice if you are wanting eggs.
My first hens ('07) were Easter Eggers. I went in with some other people (none of us wanted the minimum needed to order so went in together) and we placed a hatchery order through our co-op here. One laid an olive green egg (clearly a silver laced Wyandotte cross, black and white, no beard or muffs) and two laid blue eggs (looked more like an Ameraucana but green legged and non-standard colors). They were not friendly even though raised In the house and handled when young. They weren't skittish either, just independent, but knew who had the food and weren't afraid to come eat out of my hand. My nearby friend got some chicks from the same hatchery in the spring of '12 and she didn't get any green egg layers, just pinkish/beige and blue eggs. Hers have different feather patterns and are easy to tell apart from each other.
If you have a smaller area in which they will be confined, you may be better off with a larger, heavier breed that won't be as likely to "fly" out, buff orpington, Wyandotte, Australorp, Plymouth Rocks.
Learning all you can and planning before purchasing is a great way to spend these cold days! Welcome to the addiction that is chickens!