We use the pop up garden bin from poundland with a bin liner inside, love it, cheap and cheerful and folds up completely flat so doesnt take up much room in the car
I have the Lidl bin and use a length of elastic tied in a loop to secure the bag. The bin is very sturdy and with the lid down can be used as a temporary shelf. However, I haven't taken it for the last few camping trips as it does take up quite a lot of packing space.