how do I convince my mom to not declaw my kitten?

I don't have my kitten yet, I'll be getting it later in the year, but my mother insists that it will wreck her furniture, and said she's going to declaw it. I explained to her it's basically like ripping out their fingers but she doesn't care. I also explained to her it's cheaper to buy a scratching post that it is to pay for a declawing, but she just said it's cheaper to get a declawing than having to replace her furniture. I am furious because it is so unfair that I can't do anything about it. I need a good, convincing argument to help save my kittens claws!