I'm thinking of ghosting a girl who I liked
Why do you want to ghost her if you actually like her?
I don't like her that much anymore, she was only playing with me to get an expensive gift.
You should just be honest with her. I think that it will hurt less if she at least knows the reason why you stopped talking to her.
Why should I be honest with her when she wasn't with me? I'm not a fool.
Its not that you are a fool, but opening up to tell her might help her deal with her issues. Then prevent someone else being taken advantage by her. You can always move on and find another girl who appreciates you.