All of those countries prepared and used money called a dollar, but each country's dollar was a different value -- a changing value.

'Fluctuant value' means that their currencies 'fluctuate' or 'float' - i.e. they aren't tied to any other currencies at a fixed exchange rate. The currencies change value as the market changes - when they are in high demand, the price will increase. 'Deployed' means to put something into use. I guess that the quote relates to some period several decades ago, as that is when our currency was 'floated'.