Our fees system is the following:
A transaction cost is a charge from the underlying network transport (i.e. the Fantom Network) for processing your wallet interactions with the Swap/AMM and Yield Farm features.
Technically, when you use the Swap/AMM and Yield Farm you are actually interacting with the Smart Contracts that are setup for each service.
An example is the Native Farms - when you stake your ProtoFi LPs in the farm, Harvest your ELCT or withdraw your ProtoFi LPs, you will have to pay a transaction cost. The cost depends on the complexity of the Smart Contract process/logic, however, you will always be able to review the proposed transaction and costs in advance, before approving it. If you are using MetaMask - a transaction window should be displayed in your browser, every time a transaction has to be processed.