Does Tonstakers collect any fees?
Tonstaker doesn't impose fees for liquid staking service.
The users only have to pay regular transaction fees for calling Tonstakers smart contract: approx 0.02 TON to stake and 0.03 TON to unstake regardless of the TON amount.
Due to the nature of the TON blockchain, it is required to send an extra 1 TON for stake and 1.05 TON for unstake. The change from those extra funds (deducting the blockchain fee) will be returned to the user's wallet.