The price of repair is calculated into the asking price.

If it is obvious that it only needs an HDMI port then the listing will cost what a regular PlayStation will cost minus HDMI repair and minus ~15% for risk. So about 70% of a regular PlayStation.

Buying for repair only makes sense if you buy undiagnosed in bulk for 30% of the value after repair. You can then also scavenge some for repairs of others.