I saw Evaporust one gallon jugs in a Tractor Supply yesterday for $20, which was cheaper than the $26 per gallon at Harbor Freight.
Amazon has some suppliers selling Evaporust in 5 gallon containers with a dipping basket for reasonable prices.
Now that i know that Evaporust will only "chelate" a limited amount of rust, my revised strategy is to dip a non-delicate rusty part first in cheap white distilled Vinegar, rinse, then finish in Evaporust.