I have slightly curly frizzy hair and I want to try chemically straightening/waves, but I'm worried what it will do to my hair as it already needs dry/damaged hair conditioners and treatments and how much it will cost. Does anyone have any ideas?

If it is "slightly" curly/frizzy, why straighten it chemically? Let me just say, I hate getting chemical relaxers and if I could avoid getting them and still look presentable... I would. Why not just straighten it with a flat iron? If your hair is already damaged, putting a straightening chemical on it is a great way to make things a lot worse... If I were you, I would be happy that my hair is only "slightly" curly and just flat iron when I want it to be straight.