I use the ordinary non-reflective sheets of bubble pak sometimes in summer. I have one of the large box/rolls of the pink stuff. I don't expect to get much insulation out of it, but I use it as a ground sheet that maybe has a tiny bit of insulation.
Some of this stuff has large bubbles, and some has small bubbles. If you put your elbow down on the large bubbles, they tend to pop, so I use only the small bubble version.