Small and packable usually means down which means pricey. At the low temps you are talking about, I may wear a base layer of Capilene, a fleece jacket and a lightweight REI shell, plus gloves and a fleece beanie. I also have a down vest and a TNF Nuptse, a down jacket which could substitute for the fleece.

I'm a big proponent of buying used gear and outerwear. To get clothes on a budget, try second-hand shops, eBay or Craigslist. I got my Nuptse at a TNF outlet store. Sierra Trading Post is a good website for bargains on new items that may be last year's stock or overstock. I found a great deal on a pair of mitts there. My down vest came from a member on another site. My point is that there are deals around, but you have to spend time to find them. And yes, that big parka in my photo (not the Nuptse)? Like new on eBay.