I feel like I'm spending too much. Please tell me how I should manage my money?

Wowowowow... hold on there.
A car?
Sure, they are maybe as cheapest as $3k~
But buying a car, specially a used one is buying problems.
Let alone aside the gas, you also will spend on maintainence/insurance and many other things. Getting a car gives you a lot of benefits but it also burdens you with a lot of responsabilities.
I guess what I'm really trying to say is that:
Think about that twice, if you can handle everything that it implicates owning a car then go for it.

I'll need a car eventually, won't I?
...is what I've been telling myself. I don't know. I have to take into consideration where I'll be going to school. It'd be silly to buy a car if I end up studying overseas, which may be a possibility. In any case, it would hurt to save up the money anyway. You never know when you need a throwaway car to hide a body or something.