Fair 2nd hand price for this pc (UK)?

A colleague has an old pc sitting around that would be a good 2nd hand purchase. How much do you think is a reasonable offer for the following?

CPU: Ryzen 9 3900X 12-Core processor

Motherboard: MSI B450 Gaming Plus Max AM4

GPU: Nvidia RTX 3060 12gb GDDR6 (HDMI/DPI) Twin Fan

Storage: Samsung SSD 970 Evo Plus 2TB NVME

Memory: Klevv Bolt 32gb (4 x 8gb) DDR4 3200mhz

CPU Cooler: Arctic Freezer 34 Esports DUO

PSU: ADX 750w PSU 80+ Gold

Case: Aerocool Bolt RGB flow midtower

Case Fans: Arctic aRGB 120 mm (3 units)