I'm getting the feeling most of you don't know how much work goes into even fifty normal people.
Think about it. The cost of fifty normal people is equal to the sum total of all the work (including food) which went into raising them, plus any work they don't do (including food they won't farm) which they could have done if they hadn't died, minus any support needed for them once they can no longer work. In the milieu for Elantris, I doubt this last expense is very large because most people probably die (at least, without Elantrian help) before their upkeep becomes expensive.
These numbers add up *very* quickly, especially considering the work they could have done if they hadn't died. Think about the time and effort most parents put into raising their children. This stretches over years! Consider the cost of simply having somebody come over and babysit a child for a couple of hours (say, 8 bucks an hour) and multiply it by the number of waking hours for a typical 12 year-old. I get $560,640 just to raise a child for 16 hours a day to the age of 12. For 50 12-year-olds, just the cost of paying attention long enough to keep them out of trouble costs about $28,032,000 in modern US dollars. This is time and effort that could have been put into other endeavors if the parents had decided not to have the child.
Even if this is an overestimate, it is just the beginning of the expense of raising a child. There is also food and housing, which will add up just as impressively. Of course, in a rural economy, most of the children will begin to be effective at real work in their early teens and so start to earn back some of the resources dropped into them. If the economy is growing, they will produce more in their lifetime than was used to raise them. If they are sacrificed, however, all that future work is now lost and this future work is almost certainly also on the order of millions of dollars of lost productivity over their potential life-span.
The economy of a kingdom is just the combined effects off the productivity of all the people in the kingdom, especially if one considers farming and food. Thus any sacrifices made to produce the monks will directly impact Fjoren's bottom line even if nobody around bothers to measure it. Thus Dilaf is an extremely expensive piece of military equipment (and it shows). Brandon, I believe, understands this high expense; it is only one such monk in Elantris was actually made this way.
Of course, this brings up the reason for Dilaf's sacrifice of a single monk. The answer is: This was a flagrant waste of resources, done by somebody used to having a lot of money, designed to cow everybody around him. There are always stories floating around about the outrageous things dictators sometimes do with their money on a whim. This is much the same thing. From an economic standpoint, it was pretty stupid, but the wealthy sometimes do stupid things. After all, this sacrifice didn't just loose a person. It also alienated Hrathen. Think about that.
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