Flights there can be had at a bargain if you buy ahead of time. I regularly use the same airline (CalmAir) to fly from Flin Flon to Winnipeg. Flights at regular price will be $1500 but at sale price could easily drop to the $600 mark. You are likely flying out of Winnipeg to get there (I'm not sure Thompson gets you there).
The airline is always delayed. So be prepared for that.
I have never been there, but I've spoken to those who have. It is a beautiful place to go for the polar bears and whales. There's a reason why people come from all over the world to one of Manitoba's crown jewels
It is on my bucket list to get there at some point.
Because of the washed out rail lines, food will be insanely expensive there, but the sad thing is, the residents see that price every day
If the only way to get food there is by plane (and only so much can go at a time), the prices for basic produce (as an example) will be sky high.
Winter is very severe there in terms of snow and temperature.
I do believe that October is a great time to go to for the polar bears.
I think some tours are pricey, but it would pay to talk to people in the community. Heck, even call the school there (it's in my school division). Ask the locals what tours they recommend and then try them. I'm betting that the prices aren't all as crazy as the ones you found.