Originally posted by JeanneThompon Any suggestions on what camera I can use?
Does this mean that you don't have a camera at all?
As said, macro is a very niche area of photography and if you are at all serious about getting good results, you will need a lot of kit and a good grounding in photography. If you don't have a camera body and some experience already, that should be your first investment. Grab a used DSLR with a kit lens and start learning. Then I would suggest looking for an older manual macro lens...like that Pentax above, or Sigma and Tamron also have older macro lenses that you can grab cheap. A great alternative is to find a cheap M or A series 50mm and some cheap manual extension tubes from ebay. That with a used K-30 or similar will leave you with plenty of change.
However, once you start, you will then want lighting, focus rails, bellows, a high-end macro lens and more, so wave goodbye to any spare money you thought you might ever have...