How to get my parents to convince me to buy my friends cat?

My friend is allergic to her cat and she said I could buy it and all the things for the cat for 10 dollars and its potty trained :D I want to keep it but my dad will probably say no. How can I convince him to let me have the cat?How to get my parents to convince me to buy my friends cat?
Well, it doesn't seem that you need any convincing. You already want it. :-)How to get my parents to convince me to buy my friends cat?
Just tell him that you'll help pay for vet fees and food, you'll clean up after the cat, do your chores on time and help out with extra chores. Remind him that since the cat is litter trained you won't have to worry about accidents in the house, and you're getting all the supplies for $10.00, and it'll be much more expensive if you had to buy the supplies from a pet store. All the best!
Tell him it will be a favor for you and your friend, and make sure to tell him you will pay for it yourself, and all it's food. And make sure your dad isn't the one taking care of the cat, make sure you are!