The Levitical codes are pretty clear that usury is a crime. That is, the exchange of one form of currency for another for profit, (and by extension all profit associated with banking, etc.) is forbidden. Of course Leviticus was referring to the exchange of Roman coins for Temple coins that were the only acceptable form of money for the purchase of sacrificial animals for the Temple.
I am thinking that this bit of Leviticus is not so bad.
Today, I paid my tuition bill for Oxford. 3536 GBP = 6140 USD. It cost me 35 USD just to make the bank transfer, and I am sure that Barclays Bank in the UK made some money on this exchange as well. I don't mind paying fairly for things like food and books and education, but I can't help feeling like an economic exchange rate this poor is not so much fun.