CPU: intel i3 9100f $129
Motherboard: MSI B365M PRO-VH Motherboard $109
PSU: Antec 500W VP Plus Power Supply $59
If you are looking a PC with very similar performance and it's cheaper, you should stick to the $800 one. This one's got some very similar performance. The biggest difference in this is that it's got 16GB of RAM. It's also got a different case and power supply. If you are looking to upgrade your PC pretty soon, then this will be the better choice since it's got a 500W power supply which could support higher wattage components. It's got the same fans as the one in the $800 one just that this would have 3 of the same fans while the other one would have 2 of the shiny fans and 1 fan that came with the case. So this computer would look better and brighter compared to the other one.
Refer to this PC.