Sponsored transaction fees in sestertius: since Sept.14 2018, it is possible for you to pay waves transaction fees using sestertius since waves sponsored transaction fees have been activated for this asset. Use it at your convenience for any transaction on waves DEX or for transfers with waves or any assets.
In the case you experience a Sestertius shortage, you can buy some on waves DEX exchange, trading them for Waves:
trading them for BTC :
or trading them for ETH
See more details on sponsored transaction fees for waves assets here : https://docs.wavesplatform.com/en/waves-client/assets-management/sponsored-transaction.html