It's hard to really pinpoint specifics, as there are some overlaps, some great deals, and some great let downs in every price point, regarding modern folders IMO, very generically and generally speaking, covering large groups to try and include everyone:
You can find some real serviceable and useable functionable blades in the $15-50 range. This is a HUGE market regarding production focus, a lot of choices to sift through geared toward your average Tom, Dick, and Harry, (and Jane & Mary), who walk into a store and just want a knife, with no idea about Steel types, designer names, etc... A large selection that includes your Kershaw imports, CRKT's, Buck's, Böker Magnums, small Spyderco imports and Byrds, and many more. There are some really decent value priced knives in this bunch, but generally very basic run of the mill steel selection. Something for everyone though. But also the largest selection of crap, since the general public is generally ignorant, brands like mTech and TacForce can thrive here because they may look "cool" or "nice", and at a great price the average consumer doesn't know any better.
Even the quality brands here, there are also a lot more frequent quality control issues in this bunch...
>$50-$125 you start getting nicer designs, steel upgrades, and typically more consistent fit and finish, but still plenty of questionable brands trying to fit in and squeeze by, and plenty of over priced products that leave a buyer wanting more for their money (or not knowing any better). But lots of "nicer" knives in here; American made Kershaws, Buck Avid and Pro series', Boker+, Fox knives, Cold Steels, full sized Spydercos, entry level Benchmade's and Kizers, Mcusta's, Viper's, and the likes thereof. You also see more CF and Exotic woods, Ti liners and frames, better and more intricate milling start appearing, as well as 154cm, D2, and Powder steels start appearing regularly. For many "average" folks, who don't follow, understand, or appreciate the finer details of knives, these are many of the nicest knives they'll ever own, be the it a $60 Buck Vantage Pro or a $125 Griptillian or Manix2.
Over $125 - $400 you get into the "nice" knives, even by the standards for us enthusiasts. Premium Production and entry level custom knives, For many die hard collectors, it seems these are the frequent edc's of choice. These are the knives many of us want, but due to pricing, for most of us we can't own them all (though we really really wish we could), so we have to decide which ones we "really" want most based on our likes, dislikes, experiences, etc. Here we have our ZT's, upgraded Spyderco's and Benchmade's, Lionsteels and Pohl Force, Brous, Gaurdian, Stedemon, HTM, Emerson, Rike, Kizer, Micotech, an entry level CRK or CKF; and the design, fit, finish, form, and function is all typically top notch here; premium washers and bearing pivots and blade steels and heat treats, sprint runs, as well as many original designs by top designers... Not your run of the mill stuff at this level. This is where knives really do stand out one from another, without mistake, and consumers have every reason and right to have high expectations, bordering on perfect, for any knife in this range. Fit and Finish mistakes here are rare, and unacceptable.
-Most normal people would never get to this level. "What? $130 for a knife? That's ridiculous!" They'll say...
-Most knife folks make themselves quite comfortable here, be it their pm2, 0770cf, 810 Contego, or a small Sebbie...
Once you get up to and above $400, you're in the pinnacle of mid-techs into customs, you are a true die hard enthusiast, (or maybe you're just rich, idk), but be it a Hinder or a Medford or CRK or CFK or Shirogorov, or Marfione, or Dew Hara, Gedraitis, gold class BM, ZT limited edition, or whatever, anything over $400 is the start of the next level stuff, be it $400.01 or $2,800, this is all creme of the crop stuff. Most people in general won't be (or simply can't financially justify) touching these. To those who can and do, regularly, (bluesbender), I think it's truly awesome, not so much the financial aspect, but to be in the mental frame of mind to be able to comfortably do so with a clear conscience. I applaud you. (seriously, no sarcasm or cynicism intended here). I'm in the boat who will comfortably admire from afar, and I thank all those who allow me to continue to admire in real world application. I'm not there mentally. Maybe one day that will change.