This is the capacity of a single cell or battery, divided by the unit price of that cell/battery. The figure you get measures how much capacity one obtains for his money. This field is measured in mA·h/€. The usage of the Euro, €, is purely for readers' comfort; the original computations, and in the Bulgarian version of the site, the currency is the Bulgarian Lev, BGN.
In the table for AA/AAA cells, the data is represented by two numbers. The first one is the evaluation considering the main discharge only; the second one (in parentheses) includes the coastdown, too.
A fun fact: unit cancellation is weird! The unit for this column, as mentioned, is mA·h/€. When you multiply this by your hourly pay, in €/h, the money and time get both cancelled, and you derive a pure number in milli-amps. This is the total amount of current you can afford to buy, if you spend your money on cells and hook them up in parallel!