well there is a trial version of most of these programs. which means it's free for 30days or so. then you'd have to uninstall em and reinstall. for 3dstudiomax, i'd recommend the trial for a month. to learn the software, use the tutorial that comes with it. they're also available on the website of the company. (discreet or autodesk. not sure anymore.)
i never used poser but all i know is that its cheap. most of the stuff you make is allready made for you which sucks if you want to learn.
the tablet is like a pen and paper so when you draw on the computer, instead of using a shitty mouse, you can use a pen. it's really useful. some ppl say a 4x5 is big enough but i prefer the 6x8 wacom graphire4.
and the realistic drawing is because: if you cant reproduce something that allready exists, then how are ppl supose to know if it's your skill that made it or just a fluke? also, for anything in 3d, you'll have to draw(2d) modelsheets before going in 3d. this means for 3d, you need to be able to draw or you'll spend a lot of time guessing where things go.
would you make a house without a blueprint? thats the same.
but then again, if it's something that allready exists, you could take picture reference and try to model it in 3d that way. i just prefer drawing my own modelsheets.
good luck with all that man!