For this I could use a USB microscope, but the price is higher and they are usually too big. A normal camera can not focus closer than about 10 cm.
So I need a lense of some sort, preferably a cheap one. The cheapest one I found in my house was a loupe I use to look at SMD soldering. It is made to examine stamps, jewelry and other small things and costs just 20kr (ca. $2). Just mount it in front of the camera and suddenly the focus is down to 3-5 cm. Instant macro! :)
Step 1: Buy A Cheap Microscope or Loupe