If you’re not willing to invest it, and you don’t already have something in mind you want to buy, then I say just save it.
Aside from that it depends on your hobbies. If it were me as a teenager it might be nice to get a decent fishing rod or multitool - something that you will use for a long time into adulthood.
Saving up to travel is also something you probably won’t regret, and will create lifetime memories that define you.