Credit constituted the life-blood of the Western Indian Ocean economy. Throughout the Gulf, Oman, and East Africa, people from all walks of life needed access to credit: sultans, officials, merchants, landowners, agricultural laborers, soldiers, and seamen all relied on credit to meet their daily needs. Waraqas attest to the preponderance of credit and debt arrangements throughout Oman and East Africa: actors promised deliveries of commodities, pledged property, and put their name and reputation on the line in return for textiles, food, and other commodities.

At the same time, however, there was a vibrant cash economy. Waraqas themselves illustrate this: most waraqas describe the debt owed by the borrower in monetary terms, using the prevailing currency. Although these were usually monetary valuations for goods taken on credit, they also sometimes involved cash borrowed.

Maria Theresa Thalers (Dollars or Qirsh): The Maria Theresa Thaler (more commonly called the Maria Theresa Dollar) was first minted in Austria in 1741, and was named after the Austro-Hungarian Empress Maria Theresa, who ruled from 1740 to 1780. In Oman and East Africa, it was known as the qirsh ( (قرشor                                       riyāl faransāwi (ريال فرنساوي), and formed the basic unit of currency, and was highly popular among merchants throughout the Western Indian Ocean. Waraqas in Oman and East Africa described transactions as taking place with Maria Theresa Dollars at many different junctures. The majority of transactions in the Ocean of Paper database were conducted in Qirsh, indicated by a Q in the currency column.

Rupees: The Rupee had been introduced to East Africa at various stages: the Imperial British East Africa Company introduced it to the East Africa Protectorate (today, Kenya) in the late 1880s, and the Germans introduced it to Tanganyika in 1890. By 1906, the economies of East Africa had shifted decisively to the Rupee as a unit of currency; in Oman, the Rupee and the Maria Theresa Dollar circulated alongside one another until the introduction of the Rial in 1970. On the East African coast, the Rupee had a relatively short career: British officials replaced the Rupee with the East African Shilling in 1921; Zanzibar joined the Shilling zone in 1936, though the two currencies circulated alongside one another for some time. The Shilling gradually spread up the East African coast, into the Horn of Africa (which had been using the Maria Theresa Dollar until the 1940s) and then into Yemen by the 1960s. Rupees are indicated as R in the currency column.

Paisas are a sub-denomination of the rupee, equivalent to cents in a dollar. Paisas are indicated as a P in the currency column.

Multiple Currencies: A number of Ocean of Paper waraqas were conducted in multiple currencies. Some records will be noted at QR or RP. This indicates a transaction conducted in qirsh and rupees or rupees and paisas respectively.