Rubbermaid Brute 32 gallon w/ optional casters is what I use. Whatever you use make sure they are food grade... 32 gallon will hold about 160lbs of green.
I use a copy of the Rubbemaid Brute that are a bit cheaper, they are from Uline. 32gal is plenty for any 70kg bag. If memory is good the white/grey/yellow are certified NSF (the black and red are not....even if they are still food safe, just not certified with the stamp).
