How can I thank my mum?

My mother has been there for me when no one else has and she always helps me out when I have a problem when no on else will! I want to do something special for my mum but I have not much money and mum does all the house work and I live at home with my mum because my parents are divorced. I want to thank her somehow I have been a bully and taking it out on mum all the time. Please help.