Get the norton 4k/8k or Naniwa 3k/8k, and don't get anything higher until you can get a comfortable edge off the 8k. if you can't get a decent edge off the 8, there's no point moving up any higher. Or so I've heard, but I am just a humble noob and will happily stand corrected if this is not sound advice! but this is what I've done so far although I have been collecting a variety of stones I haven't touched anything higher than 8k apart from a brief trial of the c12k [which I would not recommend for your FIRST finishing stone regardless, but it isn't a big hit to the wallet anyway which is how I saw it when I got mine, but I still ended up buying more and more stones afterwards anyway so the money saving factor doesn't really apply anymore]