The Breeze Privacy Protocol requires a Masternode server to perform the tumbling service. Each Masternode is a Tumbler and receives the tumbling fees inherent to the process. The Masternodes require a collateral of 250,000 STRAT in order to be set up. These STRAT have to remain locked up for the duration of the Masternode’s operation. Besides this, the Masternode operator needs to have a minimum of 5 BTC. This is used in the tumbling process itself.
The Masternodes receive the fees associated with the tumbling. The fee can be chosen by the Masternode, but it defaults to 1%. This means that the Masternodes will receive 1% of all of the BTC being tumbled through them. At the moment it is not possible to know the income being received by the Masternodes. This is due, in part, to the nature of the service being provided by the Masternodes. The Breeze Privacy Protocol is, as it says, all about privacy. The only way to know what the Masternodes are receiving would be to run one, or to convince an operator to share their income. Operators are unlikely to do this as it is not in their interest to divulge their earnings and hence potentially increase competition on the Masternode server.