The transaction amount is the amount of money that will be transferred in return for the delivery of the item in question. i.e. It is the price that the seller has agreed to sell the item for and the price that the buyer has agreed to buy the item for.
The Trustap fee is the cost of using Trustap for that transaction. The fee depends solely on the amount of money that is being transferred. See the Pricing tab in the Basics section for further detail.
The total fee is the total amount coming out of the buyer’s account. This is simply the sum of the agreed transaction price and the Trustap fee. For example: If one user is buying a ticket from another user for $50, and the Trustap fee is $1.50, then the total amount coming out of the buyer’s account will be $51.50.