Doug,
you sure do have powerful tools in PS with which you can create pictures, but to achieve photorealism you nearly have to be a graphics wizard. PS is best when being used to improve or combine pictures, modify them, apply creative filters to them etc.
The name says it all: it needs photos (or something alike) to work with. Vector graphic programmes like Illustrator or Corel Draw can export to file formats PS knows (like jpg, tiff, bmp). If I didn't have access to a 3D suite, I'd use those programmes to create the picture, then import them into PS to enhance them. Which brings me to your next question.
To my knowledge, there is no 3D rendering free/shareware, nor is there something for the price mentioned.
There are however programmes cheaper than MAX. Cinema4D is one of them. Then there is a German Company called Oberheim. Their product is called Monzoom and it is -as far as I know- the cheapest. Costs about 200 US$, but I don't know, if they're still in business (their website seems pretty outdated).
Maybe there are light or demo versions of other programmes to start with, it's worth a try anyway.
André