The most important thing about what to wear on the slopes is comfort, which means warmth, nothing itchy, and nothing too tight. Sure, a person could drop $1,000 on a new get-up (Bogner for some, Patagonia for others), but that’s unnecessary. Costco and other big box stores in cold country always sell gloves and warm jackets this time of year.
If you have any technical wear at home that you use for running, biking, or even going to the gym, wear that instead of buying new base layers. You’ll need a thin, technical top and bottom, wool socks, a fleece or wool insulating top layer, possibly a down vest (if you get really cold), and a waterproof jacket. You’ll also need mittens or gloves and goggles.
Second-hand gear shops, like Play it Again Sports, often have a range of options. And you can find amazing deals on ski and snowboard wear at online sites like Sierra Trading Post.