Merchant ID is an unique numeric identifier for each merchant. It is assigned during sign-up and is visible on merchants main page after login.
In the Sites Admin under Biller Details:
Site ID is the unique ID for each site. May contain any letter or number; most I.Ds. are abbreviations of the site's name. The ID is assigned on creation and is visible in the site list.
Under Join Options:
GTBill price ID is the unique identifier for each 'Price'. It is assigned on creation and visible in the pricing list for each site.
GTBill Currency Type is the currency of the Price ID provided.
