I use lens paper (you can get that at any local camera shop) and my breath to clean my screen and glass

I wouldn't use a paper towel because they may scratch your screen (because they have tiny wood particles in them) so I would avoid using that. Or you could use a really soft cloth and get the cloth damp (just a little!) and then wipe it off.
A bag isn't really that necessary for a camera like the Coolpix because its relatively small and you dont have to carry around extra lens's, the only reason you may want a bag would be to prevent getting the screen scratched, so a little body bad would be the ideal thing for that and they are probably no more than 20 bucks (I'm not sure though

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Haha, yeah its pretty easy to upload pictures to macs