I do a lot of winter camping in Montana, and am looking to upgrade from my current 4 season bivy sack, so that I can start to push up a little higher into the mountains. I'm on a limited budget, but hoping to find something that will last me a long time, and can be used for solo trips, as well as 2 (or maybe 3) person trips occasionally with temperatures down to about -20F, with potential for some snow and heavy winds.

I've been told that a double-wall freestanding tent with a large vestibule is the way to go, but I know that might not be possible on my budget ($150 max) and am open to suggestions or offers of something else that might work. I'm hoping someone might have an older tent with a lot of wear or some extra weight that they'd like to pass along! Let me know, thanks.