Yes, it is $50 per fan and I know it is expensive—I'll save you the time to reiterate this in the comments section. In fact, this is the most expensive fan I have ever reviewed to date even besting many industrial fans. There are 140 mm versions available also for a small price increase and even there the trend would be to get a starter kit for multiple of these fans so as to save ~$50 compared to purchasing the fans and the iCUE Link system hub separately. But note that you should only consider these fans if you are going to invest in the CORSAIR iCUE Link ecosystem, as there are other products, such as water blocks and reservoir/pump combo units, which can be easily added to an existing build with a single cable each. You will also be able to get away with using the same system hub to where, in the words of a certain leather jacket wearing CEO, the more you buy the more you save (and the cleaner your PC will look).
CORSAIR is betting big on its iCUE Link ecosystem and I do get why. This is not simply a daisy-chaining setup of various fans together and instead employs a USB bus solution with way more power to allow enough fans to fill out the CORSAIR 1000D super tower to be associated with two cables heading to the hub and two other cables from the hub, all of which can be easily hidden behind the motherboard tray. Then consider the part where, for each fan, you have 34 LEDs in two lighting zones offering per-LED control of 16.8 M colors and some of the best lighting effects on the market—those new time warp modes are stunning in person. Oh, and there is also a temperature sensor in every single fan which can be quite handy for custom fan curves and to better set up your system given all the added information. These fans aren't the best performers but are quiet enough with a long RPM range to where you can really make these work for you with a little effort. As a geek who loves to build PCs and optimize the cooling and performance of various components, these fans do a good job making me want to at least give CORSAIR the innovation award. But let's not kid ourselves—the QX120 RGB is too expensive to realistically be used to the full potential of what iCUE Link can do.