Car decals are a fun and inexpensive way to show off your love for your flavor of fandom. Having themed stickers on your car can also lead to fun parking lot conversations from time to time. If you like Harry Potter, Etsy seller Good Mommy has plenty of vinyl decals to put all over your rear windshield. You can claim your kid goes to Hogwarts, call your other car a Firebolt, or just slap on the Deathly Hallows symbol.
Alternatively, you could go crazy and put one on every window; I bet the Lovegoods would approve.
See more options after the break.
Product Page ($5.99 and up)