you probably won't need a lens hood either. I have one that  came with my camera but I never use it. If you shoot a lot in direct sunlight, you might need one to block some sun to prevent glaring/ghosting.
In case of megazooms, lens hoods are usually attached to the lens housing, not screwed to the lens itself.  Your's can be different. If you really want to buy one, just do a quick search on what kind of hood people use for the camera you have and buy it.

kittys, price varies quite a lot depending on the type, size, brand, and coating of the filter. let's say, a few bucks to over 50 bucks for some nice ones. instead of spending money on the filters, degrading picture quality, and going through hassale of mounting and unmounting the filters, i'd rather suggest you to learn to play with the white and color balance on your camera and learn to use editing softwares for that purpose - much cheaper and easier alternative.