Saito.io supports feeless ETH transfers. Before sending ETH into the network, be sure you are connected to saito.io. Other nodes may or may not support this functionality depending on which modules they have installed.
Getting ETH into Saito is similar to getting ETH into other cryptocurrency wallets:
Once your address shows up, the cryptographic keys needed to access the wallet and spend/transfer funds are saved in your wallet. So remember to backup the wallet. You can do this by clicking on Account > Backup Wallet right there in the slide-in menu.
If you followed the steps, you should see your ETH balance in the Saito Wallet within a few confirmations on the Ethereum blockchain. You can then send the ETH within Saito as you would send other cryptocurrencies on the network.