Heres the answer to your question Chard...
Because soulstones are worth 3mill for the token and soulstones can be chosen as a 1st yr vet reward.(not sold but used).
And also due to the increased popularity of the commodity box... this item(the box) is actually priced on par with a 10th yr vet reward. Not alot of ppl can use 10th year rewards, again lowering the price if they have already been chosen.
*winks*