Best ND Filter for Shooting Video?

I have a Canon t4i w/ the 18-135mm STM lens. I need a 67mm ND filter for the lens. I want it for shooting video. In bright sunlight I'm often shooting around f/16 (or even higher) to get a decent exposure (because I keep the shutter speed constant). I need a decent ND filter that shuts out multiple stops of light. But there are SO many to choose from. How can I make a good choice? Any recommendations?

I'm not made of money so I'd love to hear what you think is the best bang for the buck.