There are so many ways to apply creative effects to your films and videos. You can buy dedicated lens filters or use digital assets in post-production, but if you don't have 1.) the cash to spend on new gear, or 2.) the time to spend working your magic in post, then you should try using some very easy and very cheap DIY lens filters to give your images the look you're going for. This video from COOPH shares eight of them that you can make right now out of random household items.
Even though these suggestions are aimed more toward photographers, most of them will work just as well for filmmakers. While some of these DIY lens filters require materials, time, and actual assembly, several of them are really just...things you hold in front of your lens to create a cool effect. Just be sure to get that shallow depth of field, otherwise, you'll just have a bunch of plastic or a ball of yarn in your shot. (And that ain't cute.)