Network fee
The blockchain's charge for processing a transfer, independent of the exchanger. On TRC20 it's usually tiny; on Ethereum (gas) it floats and rises at peak hours.
In more detail
The network fee goes to miners/validators, not the exchanger, and does not depend on the rate. On TRC20 and TON it is usually tiny, while on Ethereum (gas) it floats and at peak hours can eat a noticeable part of a small amount. For small transfers choose a cheap network and always include the fee in your profit calculation.
