I used to get and carry bright orange heavy duty (must be 10 mil or better) trash bags I got from the highway department (you know, those that they fill full of trash and then leave alongside of the highway for weeks), but now that I am retired I have to rely on plain old black 33 gal bags from Costco. I can usually find at least one gal and one qt sized ZipLoc Freezer bags in my stuff somewhere too...