Based on used prices around me, (NE US) my estimation would be ~$750 on piecemeal components, so if you do a small markup: $800-850 maybe. would recommend looking at similar components around you on places like FB marketplace and pricing competitively. Where you are gonna get the most ...
I regularly buy PC parts used, build them into gaming PCs, and then sell them locally on these sites. I have sold around ten computers since quarantine started and besides general questions, none of these PCs have failed or had anything bad happen to...