I don't want to give my girlfriend money.
Why don't you want to give your girlfriend any money?
She doesn't know how to budget and I'm sick of her wasting money.
People support each other in different ways, but your money is yours. You should talk to her about the way she budgets money if you think she's wasteful.
That wouldn't do any good, she'll never learn or change her ways.
You shouldn't write off your girlfriend so quickly. If you love her, you should be willing to put in the work to help her change. If not, then it might be best to end your relationship.