If you are making baits to sell, the 5 gallon route is the most cost effective way to go. You can measure your consumption by weight or liquid oz. You also need to factor in colorant, scent, bags, electricity, waste and your time. I would compare the cost and quality of your baits to others selling baits and if there is a large discrepancy try and figure out why.
You have to be competitive, but choose who you are competing with. Are you trying to compete with Academy, Bass Pro, or custom made baits?
Liquid
5 gallons = 640 oz
640 oz of CC cost $176.96
$176.96 / 640 oz = $ .2765 (28 cents per oz)
$.28 x 4oz = $1.12
$1.12 / number of baits = cost per bait (plastic wise)
Weight
5 gallons of CC will weigh close to 41lbs
41lbs x 16oz per pound = 656 oz
$176.96 / 656 oz = $ .2697 (27 cents per oz)
Weigh your bait (a 4" Croaker weighs .5 oz)
Multiply the weight times the cost per ounce (.5 x $.27 = $.14)
The Croaker uses $.14 (14 cents) of plastic.
Using the Croaker as an example, you should be able to get 8 frogs out of 4oz of plastic. With that said, you won't. You need to factor in waste as well. Your waste is going to remain fairly constant. You will have approximately the same amount of waste if you do 100 frogs vs doing 8. Why? because you can remelt sprus and plugs.
To minimize waste to almost nothing have a few open pour molds you can finish off a batch with, or save your scraps for the next time you use that color.
Don't forget to factor in colorant. As a general rule you can very safely assume 1 of our colorant will easily color 5 gallons of plastic. So you could add $6.99 to your 5 gallon cost and on average knock both of these out.
Glitter is cheap but you need to factor it in.
Your bags, 7x4 buying @ 100ea = $.18
Eyes if they are used.
Shipping of your materials. This is often overlooked but there is normally a cost associated with you getting your supplies. This is why you should buy everything from the same place

CCM

Your time. I don't sell baits. We make them for samples, neighbors, family, and personal use. Outside of that, you need to charge for your time (unless everyone is a really good friend - which may be the case from their perspective since you make baits!).
Hopefully there is something in here that helps. There are quite a few on here that make and sell baits very successfully. Maybe they can chime in and correct anything I've got wrong.
Tight lines!
Jason