Excellent point. Last week I was stocking up at TJ's and noticed new price tags everywhere. I don't keep track of the price of everything, but according to my memory, it looked like prices were jumping 10-20% on many items. Same thing with some of the food items at Costco. Costco's dog food has doubled in 3 years or so. I think this is part of the effect of the massive inflationary policies the Fed has been following.
Now I have not done the math so I might be wrong, but I don't think food supplements have risen in price as much as a lot of other foods. This leads to the idea that supplements, like say MAG-10 as a protein source, could end up being a more cost-efficient protein source for building/maintaining muscle, if you could calculate how many servings are needed to build a pound of muscle for example.
Also, time is money...if you can achieve a certain result faster with a supplement than with supermarket foods, at my age that's worth something.