Want to take vintage style photos without having to buy a new lens? How about doing some modifying? Take a dab of vaseline and apply it to your lens. The effect:

With a cell phone camera (or one you're not worried about damaging) you can try putting Vaseline directly on the edges of your lens to give your photos an out of focus vignette just like old film cameras.
If you've got nice equipment, you should probably put your grease of choice on a clear lens filter that you aren't worried about damaging.