In the US, you must be 18 to trade stocks. Your parents could do it on your behalf. The market is dropping right now, so it could be a buying opportunity. However, if you're thinking that you'll spend the money soon, like in a couple years, stocks are not a good investment. Conservatively invested stocks will go up, but over many years. Aggressively invested stocks are no more than gambling, with about the same odds, in my opinion. You might as well give your parents $1000 to go to Vegas and bet #17 on the roulette wheel.
Unless your parents are rich and could just give you a car, my advice is to keep working, and on the few occasions when you REALLY need a car (dates, for example, but not even that, absolutely...) borrow the family car.
If you pick the right stocks, buy low, sell high, yes. However, if it was easy to do, everyone would be rich. The problem is you can't know for sure what any stock will do, so it's a gamble. You could lose it all! If you play it safe and invest in a mutual fund (more than one stock grouped together), you're less likely to lose money, but growth will be a lot slower and it might take years or decades (depending on how much you invest) to save up that much money. You're better off looking for more work.
Work more. The Stock market is for people who know what they're doing. It's never too early to start learning, but as Owl says, it's a risk.
Save up, don't use stocks for short term goals.
how can you buy a $6000 car if you hardly work?
and once you get the car, you will also have very expensive insurance to pay
I'm 16 and need some money. I work but like once a month. I want to get like $4,000-$6,000 for a car. Can I do this buy myself?