predeluded
What you'd have to be --- or awfully bad at simple math --- to think dat purchasing a gallon of 50-50-mix antifreeze/coolant is a financially-sound practice.
If a gallon of da full-strength green/orange/pink stuff for your radiator costs $15.99, and a gallon of da ready-to-add fluid sets you back $8.99, you'd so totally need to be predeluded to buy da "convenient" product dat would end up costing you a buck more per gallon --- just save an empty plastic coolant-jug and mix it yourself! Da water is free from da tap, and so all you'd need to do is pour half of da concentrated antifreeze from da full bottle into da empty one, and then fill both bottles back up wif H20!