I think all of your questions can be answered with one...

I think all of your questions can be answered with one answer.

Price of the commodity or raw material is only a part, often not that big a part of the price of the product and all sort of margins need to be added. Look at wheat for example. But it applies equally to other products.

http://www.indexmundi.com/commodities/?commodity=wheat

From this graph you can see BTW that in last 7 months the price almost doubled, hence the food riots and popular uprising in Tunisia and Egypt becoming political game changers, but that is not my point.

At today's price wheat goes for 36c a kilo, being no expert but good guesser I would say that you need 1.2kg of wheat to make 1kg of flour. But the cost will not be 43c you have to add the cost of transportation, production and profit margin of the millers. Now I can buy Woolies own brand for about a dollar and that is a good deal considering more transportation, storage rents and wages. Note also that the branded products such as White Wings and others are selling for about 2 dollars a kg. Most people prefer branded products because the difference in money terms is only about a dollar more and 1kg goes long way if you just making pan cakes or the odd cake. So I would say average price to consumers is about $1.60 a kg taking ratio 20% thrift shoppers and 80% others.

That is a long way from 36c a kilo for the raw material.
Less than 25 % of the final product.

Everybody is trying to make a buck and they need to, otherwise they would not and could not do it.
Competition between producers and then retailers should keep margins in check. In this country competition is quite low at all levels, one could almost argue that state of tacit collusion is the norm.

Same goes for fuel, I am not defending petrol companies but they could easily defend the discrepancy you pointed out by claiming higher labor costs, shipping, transportation costs, interest rates and inflation, you name it .

I do not like to pay $1.40 a litre and usually buy on Tuesday or Wednesday for $1.29, sending my price signal to the Big Sisters. And buy Wollies own brand flour, eggs and milk.
I make pan cakes and put on them Wollies own brand strawberry jam for $1.45 a jar. I make lots of deserts for five bucks.

Life is sweet in this lucky country.