I have found a good place to get 5 gal. fishing buckets, Fire House Subs. Here in NC they sell the empty pickle buckets with lid for $2.00, proceeds go to some Fireman's group. Bucket with a lid at the Blue/Orange box stores are 3x that price.
Plus they are nice to have around the house/garden etc.. I just splash in a little bleach and leave out side for a few days to get rid of the pickle/garlic odor .. ready for use.