How much is a Salvage Honda Civic 2003 with 150k miles?

I got in a car accident about 3 months ago. The car is remodeled and fixed. It has a new paint job, new headlights, the airbags were placed in. I want 4,000 for it. Is that a reasonable price? It cost me $2000 to fix it.

How much it cost you to fix is irrelevant. What someone is willing to pay you for it is the only thing that matters. But if it has a salvage title, expect it to be a harder sell and personally I think $4 grand is too high.

What you spent is indeed irrelevant, Jay P is correct but sadly used Civics are high in demand by younger drivers so you might get $3,000 - $3,500.

At 150k miles the car is at end of life. This civic on ebay, same year as yours, is going for 2k and it has 50k miles on it. I think you 'might' be able to break even on it.

Deduct 20-30% from KBB private party value and that's a good estimate.

Maybe as low as 15%. The prior savage decreases the value of any car.

Without looking up the book value $4k sounds like a pipedream. And your cost to fix is not relevant.