Often times when buying lenses from stores or shops, you will always be offered filters to buy as soon as you say "I want that lens". Here are a couple of things you should and should not get.
Start with NO filters at all. I'm not one to tell someone to buy or not buy anything but almost all filters nowadays are completely useless. Any colored filters are practically of no use since any correction or effects they would offer are all done through post. However with the art of "film photography" on the brink of making a complete return, we might just yet have use to these little piece of glasses once again.
The first thing that all sales rep will sell you are UV filters. I am guilty of this. I have UV Filters on all of my lenses simply for protection, but this is my preference. Aside from that, it offers no beneficial effect on your images and may actually degrade your image quality if you are not careful.
Some will argue this, but I tend to not put these on my lenses. Although it may make your images a bit more richer colors than without, settings on your camera can compensate for this. This filter will also block any unwanted sheen from certain surfaces but may make your images just a little darker.
Neutral Density Filters
These are actually useful if you are trying to go for long exposure shots during the day or anywhere it's bright. There are Density filters out there that are variable in how much light in blocks out. These filters have a tendency to reduce color in your images as well. Depending on the quality you get, you may also lose picture quality when doing long exposure photography. Another use for this is making day time look like night time when used properly with flash.
These are absolutely nice to have and pretty much a must. There's not much else to describe about these aside from it allows you to get in close to smaller and tiny objects. These usually vary in +1, +2, +4 +10 values with +10 being as close to the subject as you can get. Macro photography is fun and allows you to delve in the world that is smaller than the human perceptive.