ok, to answer your question, you can make your maps and characters using dark basic alone but that would be hell to do, over ambitious and your not likely to get far in terms of quality
cartography shop, although i haven't got it, i think is used for making .bsp maps for stages which is primarily directed towards dark basic pro and not classic. Dark matter comes with an enhancement for dark basic classic (basically adds some cool new commands) and a bunch of professional 3D models.
the best thing to do i'd say is either or a combination of the following:
characters
- get and learn how to use a free/cheap 3D modelling program.
- use dark matter models and alter the textures as you see fit.
stages
- get and learn how to use a free/cheap 3D modelling program.
- buy and learn how to use cartography shop.
Some people make map editors and stuff to help them make thier stages, others use a 3D modelling program. see, if you don't use any of these and just have a bunch of objects, say house furniture and you want to position them, the process is gonna be filled with guess work. but with a map editor you see it all.
to live is to suffer, to survive, well, thats to find meaning in the sufferening.....