Hi, I was just wondering if I could get your opinions. I feel as if my friends aren't really good friends. I've been their friends for many years and they have never invited me to group hang outs. The other day one of my friend was telling my other friends how I'm not a bright person and they were laughing at me like I was a joke.

Plus this other friend would only talk to me if she needed something from me, like a ride to her other friends or needed help in other issues, plus I heard that they having a holiday gathering for all their friends and I wasn't invited. I just don't get it, I give so much yet I get nothing in return.

I was just wondering, are they being a bad friend or is it just me?

It's impossible for us to know without being there. Sure, friends can turn on friends, change, use people, and be quite mean, especially when in your teens. One thing that I notice is that you took it hard when one friend made not nice remarks. There's sort of an unwritten rule that if friends put each other down, you have to be able to take it and dish it back or you aren't part of the group. You have to ASSUME that you are still friends and it really is a joke, or you lose friend-status.
I'm not teenager, far from it, but just today someone wanted me to go somewhere and it was really for another reason, and I scowled and said 'HEY!' after I realized it. Took me several minutes. Then we both laughed. Then I got him to move a really heavy object for me and a bunch of other stuff in trade for going there.
All this isn't easy if it doesn't come easily to you. I would suggest that you NOT let yourself be taken advantage of anymore while you show some resolve and self confidence. And say so. If you have to find new friends who don't play these games, then do so.

Does not really sound like a friend, sounds like someone you know at work who uses others for their advantage perhaps.

The thing about friends is they come and go, and you will make many in life, so don't just limit yourself to having ones that aren't that great for you. Some friends are great, and some prove to be not so great. Its your choice who to hang with, and who you let hang with you, but you sound like you are hanging with a clique, and that may not be the best way to be for real friendship.