>>321438I've been using wool blankets as my under-the-body warmth for a couple of years now. Even a standard mil-surp wool blanket can be folded over at least once, twice if you don't toss around to much, to put multiple layers of insulation that doesn't loose significant R-values under compression under you, while still being inside the hammock.
It's dirt cheep, $20-30...and while it doesn't pack down as some air-pads do, it provides more insulation value for the bulk you carry.
If you can afford/DIY a good underquilt, it's better, but if you're doing it on the cheep...
My entire kit is still under $100, with hammock, lines, blanket, and old rain-fly as tarp. In warmer months, I JUST bring the blanket, and it does fine, in colder months, I bring a decent sleeping bag.
Another thing to consider when buying your sleeping bag, is "can I have both ends zipped open at the same time". Because if it gets cold enough, you want to be able to put your hammock INSIDE the entire sleeping bag with just the smallest opening on the foot end for the hammock to go through, and the draw-string around the head opening synched tight.
Not super comfortable, but it's kept me warm through nights when ground-sleepers were complaining.
