I'm going to cut my dad's wife out of our lives.
Why do you need to cut her out?
Because she is money hungry and is just going to try to get money from us.
I understand being frustrated at your dad's wife for that, but she is someone who is important to your dad. Instead of cutting her out entirely, talk to her and your dad and explain how you are feeling. That way you can still have a relationship with your father.
Maybe, but she doesn't even need the money. She just wants the attention. We have to stay away from her.
I understand not wanting to spend time with someone who you think is only after your money, but cutting ties with her may also make you lose your relationship with your dad. Instead of just completely cutting her out, explain to your dad what's happening. That way, he will understand and won't be so uspet.