ETH Saver uses a performance-based fee model. There are no service fees of any kind charged when entering any of the available positions, but there is a performance fee taken when exiting the position(s).
The performance fee works as a percentage charge on the amount earned on top of your deposited capital and is currently at 10% across all positions available at ETH Saver.
This fee is only taken when the position has actually yielded a positive profit. We suggest also checking out our article that explains profit calculation at ETH Saver in great detail, as well as this one that covers costs that are dictated by factors outside of ETH Saver.