According to John Sorenson, the system reported in the book of Alma followed Israelite practice before the Babylonian Exile in that the money units employed were weight units of metal rather than standardized coins. Minted coins apparently came into use in Palestine only after Lehi left there. Certainly the "money" units given in Alma 11 were proportionate weights. The inappropriate term "coinage" in the chapter heading is an error due to nineteenth century editing, not a part of the original text. Research has also shown recently that relating measures of grain to values of precious metal, in the manner of Alma 11:4-19, was an Egyptian practice. Whether there was Mesoamerican weighed money we cannot say. Most recently a burial containing 12,000 pieces of metal "money" (though not coins as such) was found in Ecuador, for the first time confirming that some ancient South Americans had the idea of accumulating a fortune in more or less standard units of metal wealth. Such a startling find in Mesoamerica could change our present limited ideas. [John L. Sorenson, An Ancient American Setting for the Book of Mormon, F.A.R.M.S., p. 233]
Pieces of Their Gold and Their Silver According to Their Value
Alma 11:4 refers to "different pieces of their gold, and of their silver, according to their value." Diane Wirth notes, however, that the word "coin" does not appear in the Book of Mormon text. Since the monetary categories referred to in the Book of Mormon refer to measures, it is plausible to assume that various amounts were used to measure a number of trade items. Cacao beans, for example, were one of the most prized possessions in Mesoamerica. Their monetary value was calculated according to their number, and--in larger quantities,--by their measure. [Diane E. Wirth, A Challenge to the Critics, p. 48]
According to a F.A.R.M.S. Staff article, there is no reason to suppose that the Nephites used any sort of coinage, although the Conquistadores found some late examples of tin and copper coins among the Aztecs. To judge from King James Version usage of "money" for Hebrew kesef, "silver" (Isaiah 55:1-2 = 2 Nephi 9:50-1), and interpolated "pieces" of gold, silver, or money, without a Hebrew equivalent (Genesis 33:19, Exodus 37:7, Joshua 24:32, 1 Samuel 2:36, Job 42:11; but see Psalm 68:31), always before coins were either invented or known to the Israelites, the appearance of the same words in the Book of Mormon can likewise be placed directly within a system of simple wieghts and measures (Alma 1:5, 11:4,20) [F.A.R.M.S. Staff, "Weights and Measures in the Time of Mosiah II," F.A.R.M.S., 1983]