Hi C.!
Your daughter is going to LOVE Boulder. It's hip, environmentally saavy, and there are tons of great deals to be had.
I would recommend
1. Craigslist! This will be helpful for big items, beds, furniture, etc. Check the Boulder and Denver areas though, some people from Boulder still post in Denver, but we have our own CL now. Areas close enough that you can
buy in are Longmont, Louisville, Superior, Westminster, Lafayette, Lyons.
2. Savers! It's a thrift store but this place is AWESOME...sometimes you can find pretty good furniture, but it's not the best for sofas. I would focus here for kitchenware, dressers, small appliances, dishes, curtains, sheets, towels, etc. I just got a almost new Bodum french press and a like new Cuisinart sautee pan for less than a few dollars each here just the other day.
3. Salvation Army. They are having great sales right now due to college kids moving into the dorms. :) They usually have pretty nice stuff and it's great for furniture. Not so good with dishes, linens, etc.
The thing to keep in mind about Boulder, there is a lot of money here, and the second hand stores are packed with NICE stuff. Name brands and high quality for a fraction of the cost.
If you are buying new, I'd check American Furniture Warehouse.
Good luck!