The fundamental problem with taking very close photos, or macros, is that run-of-the-mill lenses won't focus that close. Their closest image plane would be farther away than the sensor in the camera.
Note that macro photography is officially defined as at least one-to-one, but that's not important.
So what do you do?
- Get an expensive Macro lens
- Get a set of close up adapters, magnifying glasses, that screw on like
- Get some extension tubes
The last option of extension tubes can be very inexpensive. They are exactly that, tubes that extend the lens out farther so it can focus on the sensor. They have no optics, just open tubes with mechanical couplers for your camera. They often come in sets that can be stacked. For example:
Nikon Extension Tube Set $10
Canon Extension Tube Set $10
You will of course need a tripod, and lighting can be very tricky for macro photography.