I recently picked up a set of lenses for my iPhone off amazon and I am obsessed with the macro lens
Here's some shots with it
I first fell in love with the olloclip, but found a cheaper alternative on amazon. I am really pleased with them and use them at least once a week. I did have an issue with the magnetic piece staying on my phone at first, but by placing something with weight and/or holding it on with the initial application helped the adhesive stay much better and haven't had a problem since.