If you need a low cost solution for a filter you can probably go to your local used camera shop and just ask. Tell them you are a photography student and you need some cheap filters or better free filters. Often if you become friendly with them they will give you old gear lying around.
Alternatively just check ebay. There are lots of cheap filters to be had there! Just make sure you can get one that matches your camera. Look how cheap some of these polarizing filters are on ebay.
Now to be honest I have never heard of a dilate filter for photography so I can’t add anything of value here. What I can say is that I want you to use and think about using filters when they are appropriate. It really makes a huge difference.