Questions about painting in photoshop.

I have done a bit of 3d modeling on 3DS Max and done a bit of general photoshop use. I am now currently tempted to start attempting to do a bit of painting in photoshop.

My questions are:

Would it be worth buying a tablet for it (and which one)? It would need to be relatively cheap as its only a hobby and no idea if i would stick with it or even be able to do it.

What ebooks are the best for beginner painting, or would video tutorials be better? Not bother if the tutorials need to be purchased.

I would presume you would need good knowledge about lighting, anatomy etc. Any good reference material that could be used to help me?

And just any other help or advice people can give would be greatly appreciated.

Thanks