Why does my brother get so much more than me?

I know he's older, and i'm happy with what I have, but it seems that whenever I ask for something my mom views me as "spoiled, with an entitled attitude" yet if my brother asks for something it's almost as if he desperately needs it. I have asked to redo my bedroom for 6 months, yet my mom always says she doesn't have the money. I told her that all I wanted to to was go to the thrift store and buy some old pieces of furniture and every weekend I would ask her to take me and her response every time was "i'm not going to waste my weekends driving you around. I'm not taking you". I'm 16 and my room looks more like it fit's an 8 year old girl. I ask her for a bathing suit and she says that she already spent a lot of money on summer clothes. My brother however just got a new car, he got a 500 dollar bike, and if he wants to buy 50 dollar sweatshirts my parents don't care, yet if I want to spend 30 dollars on a top my parents freak. I'm not whining or saying my parents don't love me , and I appreciate what they do for me, I'm just curious as to why he seems to gets most of the things he asks for without getting yelled at or criticized? I know they try to treat us equally, but I sense they secretly like my brother better because he's more of a "model" son. I get c's and b's, while my brother seems to pull off straight a's in math and science without even trying. I'm more creative, disorganized and not very conventional and they don't seem to understand me so they yell at me a lot or treat me as if i'm in competent.