I have a lot of poor ass friends here in So Ontario and often considered the cheapest trip west.
First of all, you need 3 really good buddies!
Second, you'll need car access... preferably a van or SUV. Colorado is a lot closer from Southern Ontario than you think. According to mappoint.com, its about 22 hours from Toronto to Denver (versus about 35 hours to Banff). That's because you're driving in a straight line there, and the speed limits are high. I'm not sure what kind of car you can get your hands on, but I'd conservatively budget about $600 (give or take) total for gas. Split between four guys, $150 round trip isn't that bad.
Once in Denver, you get yourself a CHEAPass hotel. When I was driving up I-70, just before heading into the mountains, I saw ads at the Motel 6 for $19.99 a night, and they aren't even too bad motels (relatively). Checking the "net" rates, they're asking $40 a night, but that wouldn't be too bad between 4 guys.
From the motel, you're a little over an hour to an hour and a half away from the ski hills if weather and traffic aren't bad... but you're probably used to this skiing Blue Mountain anyways. Weekends would definately be worse. Don't worry about being away from the nightlife action, because you're a teenager, its nothing but guys that hang out at the bars in Summit County anyhow. Picture a 4-1 guy-girl ratio (or worse). Hanging out in Denver would probably be more fun (see if you can get cheap Avs or Nuggets tickets!)
The last thing is that you'll need lift tickets... Loveland, which is your closest resort to the motel (about an hour according to mappoint) has cheap lift tickets (their site has 4 packs for $99US if you preorder them). As well, you can get package deals if you want to do the Vail, Breckenridge, Keystone or Copper, Winter Park thing. A local would know the best deals better than me. Just don't buy them at the resort. Overall, I'd budget $200-$300CN
So all tolled, for four guys you have $150 (travel) + $70 (lodging) + $200-300CN = $420-520 (plus food). That is the cheapest trip for a week of skiing in the Rockies you'll find. And you and your buds would have the road trip of a lifetime. See if you can spin it that way to your parents, who you'd likely be borrowing the car from!
As well, if you can budget a little more on the lodging, check the deals at www.vrbo.com
for Frisco, Dillon, and Silverthorne. For another $100-200 per guy, you'll be anywhere from 10-40 minutes from about 6-7 resorts, and be right in the mountains.