get a fucking job? or 2? one during the day, one at night. Ive done it, both for minimum wage.
learn who in your high school sells the most weed. learn where he lives. buy airsoft gun. knock on his door, point gun in his face, and yell in your deepest voice "gimme all yo weed and money now muthafucka!!" he will give you a few hundred dollars and a quap. pistol whip the dealer and yell "i know you got yo muthafuucking safe in here, open that shit now or you gonna be bleeding a helluva lot more". pistol whip him again. he will go into his closet and give you a few thousand dollars. tell him to get in his closet, which you will then lean a chair up against to lock him in. walk away and tell no one what what you did. keep the money on the DL for a few months and voile, you have gained about 6000 dollars in three months. high school dealers are easy to rob, care about their life, and tend to be really fucking dumb.