Originally posted by madison_wi_gal BigMackCam recommended a Neweer set with ND2, ND4 and ND8 but also mentioned that Zomei is "nice" (but not necessarily referring to variable ones such as this). I might see the need for having more than ND8 so a variable one might be nice.
My suggestion is to just buy an ND8 (or 10) and leave it at that. Variable NDs are more hassle than they are worth, introduce undesirable things and unless you are spending big, are shocking quality. CPLs also have a 1-2 stop dimming effect, so they can work (in a pinch), but the basic purpose of a ND is to allow you to slow your shutter speed - a stop or two can easily be done by just stopping down the lens and sticking to the base ISO, so that makes not getting an ND2 filter money (and bag space) saved for little lose of amenity. If the scene is so bright that playing with ISO and aperture won't cut it, an ND4 is unlikely to do much either, so that makes it a non-priority too. Something in the ND8-10 range will give you loads of light-stopping power, and really let you slow things down, well beyond what you might achieve by playing with the exposure triangle. It also happens to be my most used ND filter (after I made the mistake of getting a ND4 to begin with, finding it a struggle, my ND8 completely changed my view of ND filters!).
The big advantage of the 3-piece ND set is being able to combine them for a good range of light stopping power. If money and bag space are no object, go crazy, but I suggest, given your budget, start with the filter that will give you a solid result and learn how to use it to get the effects you desire. Then re-assess. That's why I recommend the ND8. And if you don't have one, a good quality CPL filter. My ND8 and CPL are permanent features in my camera bag - you never know when they may come in handy!, other accessories are on a use-case only inclusion basis.
Of course, if you are after a very particular effect or have a special use case that requires a light ND then you should get one... but that should be obvious