Basic minimal wall damaging shelf to put an iPad mini and an iPhone 4S on?

The way my room is laid I don't have any room for a small table of any size. I have a window sill but in the morning it's sometimes wet from condensation. I'm looking for a small shelf type deal I could put on the wall to hold the iPad mini and my iPhone. We can have small holes in the wall just not large nails and screws.

Stick on type