Cheap or stupid?

[Cannibal]

I wouldn't spend the money on UQ supplies if it isn't something you need. Like slowhike said, there are plenty of practice materials out there that are really inexpensive. Look at yard sales and thrift shops for old sleeping bags. That's how I got the insulation for my current project.

[GrizzlyAdams]

Another idea would be to use an army poncho liner for an under quilt its a cheap alternative. I carry one any ways with the poncho in my pack, got the idea to do that from Sgt. Rock and another guy who did a post a lil while ago about a poncho he found. Works great so far but I have not done any testing to really cold temps yet though.

a poncho liner as UQ all by itself took me to the mid-40's for a couple of nights this summer; I sensed that was the edge of its effectiveness for me. Topside I slept in fleece top and bottom, and a top quilt.

Grizz

[Cannibal]

I've gotta quit taking lunch!

Another one of those 'that will work' moments at Target. I found a 40 degree camo sleeping bag (ripstop poly shell-poly liner) for a whopping $11.13! Again, no weight savings at all, but makes for a nice cheap UQ or a good practice project for ripping and sewing skills. It is the Target brand (Greatland) and I guess it was on clearance. For you ladies, or really secure fellas, they also had it in hot pink camo.

[ZDP-189]

Insulating material is cheap enough that you may as well use that if cost is your only motivation. You ought to be talking only a couple of dollars worth for a lining. Heck, these days even your gas fused going to the store may cost more than that!

Insulation isn't very heavy or bulky when compressed, either. Unless you are close to your maximum desireable pack weight, or the hammock is just an emergency backup shelter, I'd go with store-bought insulation.