Cells under a Microscope
An onion cell (seen through a microscope)
You can see individual cells for yourself if you can get access to a regular light microscope, perhaps at your school, or at the science museum. Kids often start by looking at an onion cell stained with a little iodine to make the nucleus and the wall easier to see.
You can also get a lens that will attach to your iphone camera that will magnify enough to see cells.