Help me repay my parents’ kindness

Good day everyone! Both of my parents are turning 50 this November and I want to repay what they have been sacrificing for me through a 50th birthday surprise. The only problem is that I am still in high school and I still can't raise any money of my own and I am the eldest. It would be very obvious if I ask money from them for their own surprise and that would be really sad because in that way they will be paying for their own birthday.
My dad lost his job when I was in middle school and until now he still hasn't found a stable job to take care of us and my mom haven't been into college because of money matters and she's a housewife. They are doing everything just so that we can study and get stable jobs of our own in the future.
They look quite young, don't they? But they are already turning 50! I can't believe it also. This is the only way I can think of how I can repay all their sacrifices for me.
Thank you for your good heart. Lots of love from me and my family! <3