These are all of the folding karambits currently in my collection, which represents a wide range in types of karamabits in terms of cost/weight/size:
1) Spyderco Karahawk -- the black one is supposedly still in production but out of stock at Spyderco; the satin one is discontinued.
2) Spyderco P'kal -- discontinued; method of deployment is entirely different than a standard karambit. A collector's item.
3) Emerson Combat Karambit Flipper but Emerson makes many others that you can see
here.
4) Fox Model 479 G10 Folding Karambit -- a "best buy" at about $156
here. Similar to the Emerson Combat Karambit Flipper which is listed for almost 2x's more.
5) Fox Model 599TicS -- my favorite and also the most expensive but Fox also makes many others for less that you can see
here. However, the CF/Ti 599TicS is well worth the $ if you can afford it. Really nothing better in terms of lightness, quality of construction and materials. You get what you pay for.
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Emerson and Fox are the best commercial sources for folding karambits. I've noted where you can find them above.
Bastinelli also makes several versions of a karambit called the "Black Bird" in your price range. Don't own and have never handled any but you can find them
here.
The Spyderco Karahawk is very good but Spyderco only makes the black Karahawk now. However, you can find both on EB for around $250-260 (plus tax and shipping cost if any).
I wouldn't buy a Hogue karambit -- too big & heavy. The only karambit that CRKT currently makes is the Provoke. Owned/sold one. Bought it as a curiosity. Way too big and heavy for normal/use carry.