So here's the deal, you can buy a bunch of little trinkets and cool things that won't affect your quality of life in the long term, or you can save up for a few big life changing things.

My suggestion would be to save up a few paychecks for a four season canvas bell tent as your first big investment. I recently moved into one as part of my offgrid prepping and wished I got one as a teen.

Its essentially your own room outside the house (provided your parents backyard is big enough for a small tent). Why? A reliable long lasting portable shelter that you can live in and or have a place for your friends to hang out/ socialize. If your parents are the loud argumentative never stops fighting kind that get on your nerves, being able to just leave the house and go to your own personal sanctuary is a godsend. If you get comfortable enough with tent living it will open up to you the possibility of saving up money for cheap land and owning your own property somewhere nice and scenic. without ever getting into financial debt.

If you are a smoker particularly of pot invest in a nice dry herb vaporizer from arizer. The smoke is a lot less harsh on the lungs, there's practically no smell (my parents HATED the smell and chewed my ass when they caught a whiff)