You are being exploited by the metalworking bourgeois! I have seen their pitiful offerings of two or three coins for whole baskets of bread, and they aroused my anger. Why is their labour worth so much more than yours? Do they honestly believe that making a single bar of cast iron and pressing it into coins is as much work as baking 800 loaves of bread and harvesting the wheat required for them?
It takes about equal time to mine a piece of ore (with a pick, naturally) as it takes to harvest a measure of grain. A metalworker that hasn't even specialised for an industrial lifestyle can get one bar of cast iron from ten units of ore with average luck. If he makes efficient use of his smelting facility, he will also require 0.16 lumps of coal per lump of ore smelted, so production of a single cast iron bar consumes 10 lumps of ore and 1.6 lumps of coal. Making coal actually takes less time per lump than mining ore, but given that the collier also needs to replant every tree he cuts down (not that the bourgeois is so considerate), we can generously assume that it takes same effort to produce a lump of coal as it takes to mine a lump of ore. So, a bar of cast iron takes labour equivalent to harvesting 11.6 measures of grain. Let's be generous again and say it's 12 measures.
Now, given that it takes two measures of grain to make a bread, it can be said that it takes roughly the same amount of labour to make 6 loaves of bread as it take to make one bar of cast iron. At 99 coins to a bar, this means that a loaf of bread is worth as much as 16.5 cast iron coins. Let's be generous again and round it down to 16. However, as the spectre of capitalism still looms over us, we have to also take the market forces of supply and demand into account. If we give them absurdly unfair influence on prices and allow them to lower the price of bread to just one quarter of it's real price, the bread will still be worth 4 cast iron coins per loaf.
So, my farming brethren, I propose we form a united front against this shameless exploitation and set the minimum price of bread to 4 cast iron coins per loaf. Anyone who sells for less is a fool for letting himself be ripped off so badly, and will surely perish in poverty, so no action to enforce this minimum price will be needed. All that is needed is that you all become aware of how much your labour is worth.