Should I buy an NFL Teams decal?

I just saw an ad where you cam buy a set of decals of your favorite NFL team and paste them all over the side of your truck. The decals are so big it looks like an advertisemnt wrap. My problem is should I buy the decals to show support for my favorite team or should the football orginaztion pay me for marketing their product? I think they should pay me, then I can afford o attend a game and maybe even pay fo parking.