You can also look at cookies.
As per your way of seeing it, a cookie will give you the profit of:
2 milks at 260
2 grains at 60
2 flour at 110
Productioncost at 170
Total costs 1.030 to be sold at 2.035 = a profit of 1.005
That would be a very bad way of seeing it.
2 milks at 420
2 flours at 450
Production cost at 170
Total costs 1.910 making you a profit of 125 for 1 hours work of 1 regular and 3 milk trucks. Hardly worth it, right?
Kel, as far as I remember, you said you worked at a bar, right?
Imagine this situation:
You sell beer there, and business is just bad, you loose money every day.
You win the lottery - and you buy the brewery you buy the beer from. Great business that brewery has going, makes a lot of money - however, does that make your bar profitable? Would you lower the price from the brewery to your bar to make profit in the bar, when you could sell it to someone else much higher?
Of course (or I should say, I hope) not (unless you were philantropic, and felt for the bar - but then it is no longer business for profit).