hummingbird gibson guitar

Teens help me out, How do you convince your parents to get you something.?
I’ve been playing on a rented guitar for a while, 7 months perhaps. My parents decided to buy me a actual one. They already know i’m commited. I am, I really in love with playing guitar.
But my parents only want to spend 100 dollars max on a guitar! A close family friend is willing to give me her Gibson hummingbird for 300 dollars because she is quite wealthy and understand my situation. My parents aren’t buying though. They think every guitar is the same. Its a freaking Gibson HUMMINGBIRD,
I’m not a brat, spoiled or whatever. I tried to get a job and pay for it myself, but they won’t let me. They think i’m wasting my money on a “typical” guitar and have showed me a First Act one at Wal Mart for 80 bucks. My family isn’t poor, I know that for a fact. We are quite well off. My parents are just being cheap.
Any adivce?
Tell them that. Tell them that playing a cheap guitar will make you sound not as good and you won’t be motivated to play it. Also, you could talk them into spending an extra $50 and going in halves for the $300 guitar.
1966 Gibson Hummingbird