Most of the “stuff everyone should buy” is stuff you really don’t need as a teenager, like cast-iron cookware or a stand mixer. If you have hobbies you want to pursue, you should find a specific group around that hobby and ask them. A lot of black Friday “deals” aren’t really deals, though - some companies will actually produce lower quality product lines specifically for black Friday sales, so if you end up buying something big like a TV or something like that make sure you do a little research.
If you want general financial advice, I wouldn’t put it in a retirement account like the other guy said. You have plenty of time for that, and you probably have milestones coming up that you’ll want money for - buying a car, graduation celebrations, going to college, getting your own place, whatever. So saving it for that kind of stuff is never a bad idea.
The ten crack commandments