Depending on what you have to begin with that can be taken over to the new PC can cut some cost from your build to use in other areas. Also knowing what to buy and when can trim some money off your budget. The case, the peripherals (keyboard, mouse, and other input devices), and possibly the CPU along with the gaming monitors are some of the items you will not have to buy when building a new PC. Doing the quick math that is around 2300 USD which can get you a really powerful rig. For a Ryzen build figure $200 for a Motherboard $700 for a 2080 super GPU 400 for 64GB of 3600mhz ram about 100 for a 1tb M2 SSD and about 500 for a Ryzen CPU. This will leave you with about $400 USD left over for a Power supply or a new gaming monitor. With the right monitor or VR setup, you will be running 144mhz at 4K no problem. It is always cheaper to build your own rig.