Geez $300 for headphones, seems like that might be enough impulse spending out of it. How about spending some on something gramdma would be proud to see. Maybe some home technology study stuff like a robotics kit, a 3D printer and supplies, or may be just a camcorder for working on videography skills.
Being a creator of entertainment and not just a consumer may provide a greater sense of satisfaction and maybe equp you to have a unique business in the future.
Shapeways.com is a 3D printing service people upload designs to, sort of like teeshirt on zillow.
Gee, in a couple years you will discover cars and girls and you do not see any point in saving up money? {At least the $500. You do seem to enjoy those headphones.
$20,000 is a tidy amount, but life is expensive, so keep adding to it.
Give it away then. You don't need more stuff. Do something valuable that will help someone else if you don't need it.
you WASTED $300 on headphones
You could buy a trampoline!