Depends on the tubs

If you keep BP 41 quarts tubs are all you need they can be found anywhere from walmart to target to lowes etc

If you want to keep larger animals such as Blood and need a BIG tub you need to look for IRIS V175 which you can usually find at Walmart around this time of the year sold as Christmas Tree storage box.

Never seen any 5 or 6 feet tubs locally.