Surf does not take a commission, but there is a commission in the blockchain.
In the Free TON blockchain, the commission is charged from:
initialization of the wallet;
transfer of tokens;
Surf automatically calculates the commission for your transfer. The transfer fee is paid by the sender. It depends on the amount of the transfer and is quite small.
When you transfer Crystals, use DeBot, or send funds to staking, you launch the necessary smart contracts. The execution of any smart contract on the Free TON blockchain is paid. This fee is called “gas” and is paid by the Crystals. The more computing power is used by the smart contract you have launched, the higher the commission for its execution is.
Your messages in the Surf chat are not subject to commission.
You can read how fees are calculated on the Free TON blockchain at zeroheight.com.