Fees play a crucial role in the incentive structure of both Bitcoin and JoinMarket. They form the basis for the economic incentives of both systems. In Bitcoin, you pay fees to a miner in order for your transaction to be included in a block. The higher the fee you are willing to pay, the higher the likelihood that your transaction will be included quickly.
In JoinMarket, you pay fees to market makers in order to use their liquidity to your advantage.
Consequently, when you are sending a collaborative transaction in Jam—or when you are using the scheduler to do multiple transactions—you have to pay fees to miners and makers. How high these fees are depends on market and mempool conditions.
Of course, you can offer liquidity yourself via the Earn functionality, allowing you to be on the receiving end when it comes to maker fees.
Paying Maker Fees
How much you will pay in maker fees depends on the fee market of the current offers. You can get an overview of fees by inspecting the order book.
Paying Mining Fees
Just like all users of onchain bitcoin, you will have to pay transaction fees to miners.
Note that collaborative transactions are larger, in terms of bytes, than "regular" bitcoin transactions. Since the cost of an onchain transaction is determined by its size in bytes—not by value transferred—a collaborative transaction is more expensive than a simple spend.
Earning Maker Fees
Make sure to check the orderbook to compare your offer with current market rates. If your offer isn't competetive, nobody will take you up on it and you will earn zero sats.
All fees are denominated in sats. Use one of the tools below to convert them to fiat:
See also "a note on fees" from the JoinMarket documentation.