How far are you from the MN border? If close by, theres a shop about 15 miles up on HWY 63 that has once used barrels that contained coconut oil. 10 bucks each in perfect condition, but you better hurry, they only have about 300 of them LOL.
There is an ad in our local shopper paper about every other week or so, for like $5.00 or $10 a piece. Let me know and I will try and get you the number or pick you up a couple and figure something out. Hope this helps.
this guy in Laporte City Claims to have brand new ones for $10, not sure if they are the right size, if you plan on using weber parts make sure you get the right one as 55 gallon barrells come in about 14 different sizes
I know of a place here in des moines that sometimes has food grade barrells so let me know if you need their info.