It is not cheap to dine or stay in YK but it is possible to cut some expenses. There are a number of free places to visit such as the Legislature, Prince of Wales Museum, visitors Centre and shopping. between the Ledge, POW and visitors centre I spent almost a full day. There is a lot of scenery and parks that can also be visited for free.
I took some CDN McDonalds coupons which they honored. I had a few meals there but there are a lot of restaurants with some of the best food I have had anywhere on my travels. Just go to Trip Adviser "restaurants" to read the reviews and you can't go wrong. At the Quarry Restaurant in the Nova Chateau I had the Chef's special which was excellent value. Most restaurants have these specials.
You can also pick up breakfast items or ready made meals at a grocery store such as the indepent store in the centre of YK as i did to have meals in your room.
to cut the cost of accommodations there are also a lot of private homes with B&B being a great example. i stayed at the birches and didn't have breakfast as my room had a kitchenette in it.