It is sometimes said that in ancient times salt was so precious that it was counterbalanced in gold. The first reports on a value of salt date from the Roman period. Prices from salinas near Ostia/Rome for a small bag of salt given as a gratification for an officer suggest that 50 working days were remunerated with a kg of salt. The value decreased to around 35 working days per kilogram of salt until the early days of the first millennium. Around the year 1000, the value of 1 kilogram of salt from an Istrian salina was reported to be the equivalent of 0.6 gram of gold or roughly 11 working days. Around 1600, 1 kilogram of Bavarian salt was worth 1 kg of beef, while 1 kg of Swiss salt was equivalent to 0.1 gram of gold or three working days. By 1700, the value of 1 kilogram of salt in France was equivalent to one working day. In 1850, you could buy a kilogram of salt in Ethiopia for as little as 10 chicken.
Over the past century, prices further declined quite drastically, and today the price of salt in brine for chlor-alkaline production in the Gulf Area is below 1 US cent per kilogram. Assuming an hourly rate of US$17, a kg of salt is equivalent to 0.000006 hours.