This is for those with commitment issues or those who are having trouble decided whether to get pvp gear or pve.It's might not exactly be an exploit, but a neat trick.
As many of you know, you can buy things from vendors with badges and honor and such and return them within two hours to get a full refund. This is nice if you are low on badges and want to do both, or just don't want to spend your marks permanently. Buy yourself some pvp gear, go pvp. When your done, sell them back, get your marks. Want to go do some Heroics or Raids and your bracers could use and upgrade? Go buy them and return before two hours and get your marks back.
I'm currently having fun with this pvping.