Small mom and pop liquors stores have tons and tons of milk crates that they can give you. (I know bcz I own a liquor store) 6 gallon crates are dime a dozen. But the 4 gallon crates, ah yes, the Holy Grail of genuine milk crates, those are the ones to get. And if you find one, be sure to U-Lock it to your rack because zip-ties won't secure it for long.