What is the best way to handle clients who ask for free work because others have done it for them?

[Btaliat]

There are many clients on freelancing and it is always better for the freelancers need to know more about this. There are some clients that may even be asking the freelancers to do the work for them for free just because they have gotten it for free with some other freelancers. How do you think a freelancers should deal with this? You only need to tell them politely that you don't offer such an offer. And they should try the ones that have used before.