I've a couple of Rab & Terra Nova down bags. They're good quality.
Sorry - but if want something that's small, light and is going to last it's going to cost more than your budget.
I don't know the Alpkit.
Some of this kit comes up on eBay. Use a liner, a fleece hat and HH tops & bottoms (for example) if you're looking to extend the bag's range.
I also have the Rab survival bag outer HERE or the Terra Nova's MOONLIGHT

