Is borrowing money from another merchant to break a thousand dinars, when I don't have the necessary change, considered a trick to circumvent usury?

The exchange can take two forms: one is permissible, which is that the exchange is only for the price of the commodity, and the remainder of the thousand dinars remains a trust or a loan. This is not usury. The other form is forbidden, which is to exchange based on one thousand dinars for such and such of another currency, then some of it is given and the rest is deferred. This is not permissible due to the condition of immediate possession (al-taqabud). For in the Hadith: "There is no harm in taking them at their day's price, as long as you do not separate and there is something between you." As for converting the currency into smaller units, there is no harm in it if the price of the commodity has been paid in full and the remainder has been loaned, as long as the loan is not a condition of the sale, because then it would be a loan that brings benefit, which is forbidden.