Carousel Costs

I'd like to know who determines the price of groceries these days. Why is a 2-liter bottle of Coke only $0.89, while the 20 oz version will run you up to $1.50? It makes no sense.

This crosses my mind as I look at the tins of General Foods International Coffee, Viennese Chocolate Cafe on my desk. I buy these coffees from Target, because at my local grocery store, Shaw's, they cost $3.99. Target will always beat that price.

But the price isn't static at Target. When I first noticed they were cheaper at Target, the tins ran at $2.79, sometimes on sale for 2 for $5. And then came a huge price hike--to $3.54--but only for the Viennese Chocolate Cafe flavor. It was still $2.79 for Swiss Mocha or the Cinnamon Dolce. When I brought this up to the Target management, I would get a knockdown on the price at the register--but they wouldn't change the shelf price to match every other flavor.

Then magically, the price went down again to $2.54, for all the flavors. And now it simply jumps around. I have two tins on my desk right now, one with two labels: the tin began at $3.24, but I bought it for $2.54. The new tin I'm about to crack open was $2.99.

What is the point of this up and down? What is the actual value of a tin of instant flavored coffee mix? (And yet, all in all, it's still much cheaper than Starbucks.)