You can buy it as a part of Kurfürst and The Channel for $69.98 USD
Like previous DCS World titles, DCS: Bf 109 K-4 Kurfürst features a painstakingly reproduced model of the aircraft, including the external model, fully interactive cockpit, mechanical systems, and a Professional Flight Model (PFM). Along the lines of our DCS: P-51D Mustang and DCS: Fw 190 D-9 Dora titles, DCS: Bf 109K-4 Kurfürst places you behind the controls of a powerful, propeller-driven, piston engine combat aircraft. Designed long before “fly-by-wire” technology was available to assist the pilot in flight control or smart bombs and beyond visual range missiles were developed to engage targets with precision from afar, the Kurfürst is a personal and exhilarating challenge to master. Powerful and deadly, the last production model of the only single-engined German fighter to see service throughout World War II, the Kurfürst provides an exhilarating combat experience to its drivers, and a worthy challenge to all fans of DCS: P-51D Mustang.
Key Features of the DCS: Bf 109 K-4 Kurfürst:
Minimum system requirements (LOW graphics settings): OS 64-bit Windows 7/8/10; DirectX11; CPU: Intel Core i3 at 2.8 GHz or AMD FX; RAM: 8 GB (16 GB for heavy missions); Free hard disk space: 60 GB; Discrete video card NVIDIA GeForce GTX 760 / AMD R9 280X or better; requires internet activation.
Recommended system requirements (HIGH graphics settings): OS 64-bit Windows 8/10; DirectX11; CPU: Core i5+ at 3+ GHz or AMD FX / Ryzen; RAM: 16 GB (32 GB for heavy missions); Free hard disk space: 120 GB on Solid State Drive (SSD); Discrete video card NVIDIA GeForce GTX 1070 / AMD Radeon RX VEGA 56 with 8GB VRAM or better; Joystick; requires internet activation.
Recommended VR systems requirements (VR graphics settings): OS 64-bit Windows 8/10; DirectX11; CPU: Core i5+ at 3+ GHz or AMD FX / Ryzen; RAM: 16 GB (32 GB for heavy missions); Free hard disk space: 120 GB on Solid State Drive (SSD); Discrete video card NVIDIA GeForce GTX 1080 / AMD Radeon RX VEGA 64 or better; Joystick; requires internet activation.
This product can be downloaded and installed through the DCS World Module Manager. If you do not have DCS World installed, you can download the DCS World web-installer by clicking this link. If the product description does not have information about which DCS World version you should install, you only need to have the "Stable" version DCS World installed on your PC.