Debt settlement services charge you a fee to negotiate a debt settlement with your creditors. The amount of the fee that they charge you is going to vary based on the service. They might charge you a set fee, or a percentage, or they may charge you a set amount to create a debt settlement plan and then another additional fee to actually manage the plan. In any case, before you decide to enter into an agreement with a debt settlement service, you need to confirm that the full fee structure is clearly outlined and that you are aware of exactly what you are to be charged.
You should also think carefully about whether working with a debt settlement service is the right choice for you. While there are some legitimate debt settlement services out there, there are also services that are scams and that promise you things that they cannot deliver. Many are also not upfront about what they do- they may tell you they can settle your debt for pennies on the dollar, but what they don't necessarily tell you is that they might severely damage your credit score in the process.
Before you decide to work with a debt settlement service, you should strongly consider speaking with a debt settlement lawyer instead. Debt settlement attorneys have the same relationship with credit card companies that debt settlement services do, and they have excellent negotiation skills so they will be able to work with you to get your debts reduced. Further, debt settlement lawyers must adhere to the attorney's professional code of ethics, which means they must put your interests first, they must be licensed, and they must be up front and fair about their fees charged.