How Do I Repair a Broken Zipper?

Take the pull thingy right to the bottom of the zip and using your sissors snip the teeth of the zip on the opposite side, slide the pull gently into the teeth and pull up~now you have a working zip again.
Stitch firmly just above the snip you made making sure you catch both teeth as if you pull the zip down below the cut you made it will pull off.

There really isn't an easy way to that, you pretty much just have to buy a replacement zipper and either sew it in yourself or have someone else do it.