I had my PC for 3 years and it has:
CPU: i7-4790 /// GPU: 1050ti 8gb /// RAM: 8gb DDR3 /// HDD: 2TB
I'm unsure about the rest of the specs as it is a prebuilt. Any ideas how much I should sell it for?
There is not enough info here for people to really give you a price...
A few things that you need to add What shape is the PC in You said a prebuilt, so what is the brand What extras would come with it, mouse, keyboard, monitor other stuff.
https://www.cnet.com/products/acer-predator-g3-605-tower-core-i7-4770-3-4-ghz-12-gb-2-tb/specs/
This one is slightly different than mine spec-wise.
I am only selling the PC