In my ongoing search for prices to put a little meat on the financial dealings of the Mormons I have found some treasure troves too large to exploit in a single sitting.
For starters, there is the Congressional record itself, which in the debate records and in the journals of decisions mentions the odd price. The Statutes at Large, which record the actual decisions reached--e.g. duties levied on important goods in 1789---and contain records of the expenditures, such as annuities for the Indian tribes. The Journal of the Senate enumerates supporting actions---such as the elimination of navigational obstacles in the harbor of Mobile, Alabama in 1832.
Furthermore, the library of Congress has undertaken a massive project to digitize newspapers, called Chronicling America, which could use some further investigations. Many of theses newspapers came into being as part of the transformative process 1815-1848, and thus fall at the tail end of the Mormon period of investigation, but some earlier ones are present as well.