Name of the Tier. Defaults to Tier 1, Tier 2, and so on.
Starts at Unit
The first number of Units for which the price for this Tier in the Rate Plan will be applied. You define the starting unit for each tier after the first. The first will start at 1 or the equivalent, depending on the number of decimal places. For example, if you choose 3 decimal places the first tier will start at 0.001.
Ends at Unit
A value, or Infinite. Ends at units are calculated based on the Starts at unit of the next tier. The last tier is infinity. This is also based on the number of decimal places. For example, if you select 3 decimal places and start the second tier at 5.001, the previous tier will end at 5.000 (or 5).
For each currency, specify a price to be applied for units rated in this tier. (Note that depending on Price On choices, all usage will be priced at this rate for just the usage that falls in this tier.)
Click Manage Currencies in the Action sidebar to add or remove currencies. You must have at least one currency.