Sole selling rights
Most of us engage the services of an estate agent when trying to sell a house, and all agents charge commission.
However your house comes to be sold, even if you reach a private agreement which has nothing to do with an estate agent, you'll have to pay the agent their commission.
Never agree to sole selling rights unless you're 100% sure that you won't find purchasers from your own efforts, or that you definitely won't be instructing another agent.
This leaves you free to sell privately by your own efforts without paying any commission, but not through other agents.
You can instruct other agents, but if they sell the house, you will have to pay commission to the original sole agent as well as paying the agent who sold the property.
When you agree a sole agency with an estate agent the contract will usually state how long this period of sole agency will last.
At the end of this period, you're free to use one or more additional estate agents.
If you're thinking of using more than one agent, it's probably best to enter into a joint agency, whereby you instruct two agents.
Both have to agree to this, and then must agree to who gets the commission on the sale, which may be shared.
If you enter into a multibuy agency agreement, you can instruct as many agents as you like, and the one who comes up with a buyer earns the commission.
The fee for this type of arrangement will probably be the highest of all the options available.