I recently came across an inexpensive lens at my local "Old Navy" store. It was on sale for less than a dollar and worth checking out. It was easy to use. There is a suction cup surrounding the lens that helps it attach itself to the iPhone. That being said, the surface must be fairly clean for it to adhere well to the iPhone. Below are a couple of pics that I took with it. The first is a pic of a green birdhouse without the lens.
Then using the lens. You can see that it just adds a fun "star burst" type of effect to the picture, which seems to make the colors pop a bit more than the photo I took without the lens.
Anther shot of some hydrangea using the iPhone camera.
The same shot using the "Jelly" lens.
I also found that the lens can be offset a bit to create some other effects. So here is a pic of a succulent plant that I had in the yard.
Then by off setting the lens and taking a close up of just part of the plant, I was able to capture the image below.
It came out pretty cool. I have to say that it was a dollar that was well spent. I have had a bit of fun with this lens. If you keep your eyes open for good deals on these types of lenses, they can be found pretty cheap and are fun to use.
If you are looking for a more expensive collection of lenses, then you may want to check out the Photojojo site or Amazon to see what is available.