To add to Alan's comments, if you do buy a protective filter, make sure that it is a high quality multicoated, clear filter. Companies such as Hoya, B&W and Nikon make good filters. For a good 52mm filter expect to pay anywhere from about $35 - $45. Low quality filters can substantially degrade the quality of your photographs. If the filter is priced at about $10-$15, skip it.
Here is a link to the hood that you had asked Alan about.
The filter is a good one, but don't buy the hood. Buy a genuine Nikon hood that is made specifically for your lens (the one that JP linked to). The hood on Amazon may block the corners of the frame (vignette) when the lens is at the wide end of the focal length, i.e. 18mm.
Most of us use the hood all the time. It's not necessary in the bag, so mostly these hoods get reversed onto the lens and stored that way. But occasionally that's a packing problem and so the hoods get transported separately. (Mine occasionally go wrapped in or around socks.)
_____ Brian... a bicoastal Nikonian and Team Member
My gallery is online. Comments and critique welcomed any time!
Welcome to Nikonians! Yes, using a hood all the time is best practice. If your bag is large enough to hold the camera and lens with the hood in the shooting position, there is no reason that you can't pack it that way. If your bag is smaller, just reverse the hood when you pack it in the bag. It only takes a second or two. Good Luck and Enjoy your Nikons!
The advantage of using a hood is it often results in better colour and slightly sharper images - because it reduces unwanted "flare" light reaching the front element. The 18-55 does not come with a lens hood so buying and using one is a smart move.
Photography is a bit like archery. A technically better camera, lens or arrow may not hit the target as often as it could if the photographer or archer does not practice enough.