Hapi: An appropriately named fertility god.
http://www.touregypt.net/featurestories/hapi.htm

The Egyptians generally did not use coinage for money, not until very late in their history. Even weighed metals like silver were not as preferred as the bartering of livestock, food, or goods.

The closest thing the Egyptians had to a real coinage system is the deben: or about 92 grams of metal, ten kit equalled one deben.

Most daily transactions were based on oral agreements, given the fact that the sums involved were often small, people could neither read nor write and scribes were not always available. But when the amount was significant, the wise lender had it put in writing. IOU's were written on pot shards or any other piece of matter flat enough to be written on.
Example
Owed by Apahte, son of Patai: 30 pieces of silver.
Written in the year 28(?), on the 30th of Mesore.
http://nefertiti.iwebland.com/trade/internal_trade.htm