Buying new computer

Solution
Building it will be much more beneficial for you...

Intel...

PCPartPicker part list / Price breakdown by merchant

CPU: Intel - Core i5-8400 2.8GHz 6-Core Processor (£155.00 @ Kustom PCs)
Motherboard: Gigabyte - B360M DS3H Micro ATX LGA1151 Motherboard (£59.00 @ Kustom PCs)
Memory: Corsair - Vengeance LPX 8GB (2 x 4GB) DDR4-3000 Memory (£55.00 @ Kustom PCs)
Storage: Western Digital - Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive (£34.74 @ Aria PC)
Video Card: Gigabyte - GeForce GTX 1050 Ti 4GB Windforce OC Video Card (£128.00 @ Kustom PCs)
Case: Cooler Master - MasterBox Lite 5 ATX Mid Tower Case (£37.49 @ Kustom PCs)
Power Supply: Corsair - CXM (2015) 450W 80+ Bronze Certified Semi-Modular ATX Power Supply (£43.00 @ Kustom PCs)
Total: £512.23
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-08-21 18:30 BST+0100


AMD...

PCPartPicker part list / Price breakdown by merchant

CPU: AMD - Ryzen 5 2600 3.4GHz 6-Core Processor (£141.00 @ Kustom PCs)
Motherboard: Gigabyte - B450M DS3H Micro ATX AM4 Motherboard (£67.20 @ Aria PC)
Memory: Corsair - Vengeance LPX 8GB (2 x 4GB) DDR4-3000 Memory (£55.00 @ Kustom PCs)
Storage: Western Digital - Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive (£34.74 @ Aria PC)
Video Card: Gigabyte - GeForce GTX 1050 Ti 4GB Windforce OC Video Card (£128.00 @ Kustom PCs)
Case: Cooler Master - MasterBox Lite 5 ATX Mid Tower Case (£37.49 @ Kustom PCs)
Power Supply: Corsair - CXM (2015) 450W 80+ Bronze Certified Semi-Modular ATX Power Supply (£43.00 @ Kustom PCs)
Total: £506.43
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-08-21 18:32 BST+0100


You can activate Windows later on. There will be no performance difference even if you dont... https://www.howtogeek.com/244678/you-dont-need-a-product-key-to-install-and-use-windows-10/
 
Solution
kacper03.tylko, are you interested in this unit for gaming? Most builds these days include a more robust build especially with drives. Most use an SSD for OS and frequently used applications(focuses on speed) and a mechanical drive for storage. Something to keep in mind.