My parents treat me like sh.it?, they dont care about me?

Last week, it was my birtday and i dont get anythin than $10, they sould give me $100 because they gave me $100 wene it was my birthday wene i was little, and their not poor, the next day, my sister ask them for $100 give ito her, she dint use it for somethin important, just to get a ipod, and it was not her money, It gets me in my last nerb, five days later, she gets a party, its not even her birthday. They make her so huge the partys and wene they trow me a party, wene i was little, it was so small, also, wene she ask for something she always gets it, wenever i want the samething, they never give it to me and the buy to her, always, im 15 years old, and shes 10 yers old, what should i do, i cant take it