Is this thing my parents (mom) do normal?

So, I got pocket money of 200čk/month (except my mom forgets like every third month, but lets say its an every month metter), which leaves me with 2400kč/year. I am totally not mad at that, thats amazing, the question is: is it normal I pay for stuff my parents should pay for, like guitar lessons that my mom wants me to take(1000kč/5 months) and school stuff like ice skating (50kč/each). So i dont have 2400 pocket money a year, but about 250kč a year. And I wouldn't question it if my brother had the same rules, but he doesn't. My parents pay for school everything, when he asks for money when he gies out he gets them etc. So yeah, is this normal stuff to do? Do/did your parents do this?

(2400kč = about 102$)