Anyone use them?, what type?

Used to get wax paper hotcaps years ago, last I checked they got stupid expensive....would use gallon milk jugs, but don't know anyone that drinks milk, lol

would prefer cheap, or better yet free,

Whataya got?

I have used the small plastic bags from grocery stores or other stores that have them. When I was selling to a road side stand years ago they workked very well and where free and just saved them every time we went to the store. A few sticks around the plant cover and push some dirt up around the plastic.
I still use them but not near the volume I did because I don't have that many plants now.