I know it depends on the market I am buying in and the cost of the various components. I've made a few items from mdf with shellac finish lately and I really like the way it works (clothes storage in a basement) and I want to make more. I figure I have enough projects to warrant two gallons of shellac and at $45 a gallon I want to explore mixing my own. But is diy mixing beneficial more because of the quality and customizability of the product rather than cost savings? Like, if I just want to save money should I just buy the premixed bc there's not really savings?
The flakes have a much longer shelf life than mixed shellac, somewhere on the order of 3 years vs 6 months depending on environmental conditions. That makes the flakes a better value if you can't use an entire can at once. I suspect you won't find much of a price difference. The harvest is really the largest factor in pricing.
You are correct about the customizability. Flakes can be bought in a variety of hues, where as the canned is likely blonde. Being able to precisely control the cut is nice when it comes specialty uses such as refinishing and French polishing. (You know, in case you want to seal away tobacco odors or get a piano-like finish. Or refinish a piano played by a heavy smoker.)