Which online car buyer pays the most?

There is no universal answer; it varies by vehicle, model, mileage, and timing. Carvana, CarMax, Vroom, and local dealers all fluctuate based on their current inventory needs. The only way to know is to get quotes from all three simultaneously and compare. Generally, a private sale on Marketplace or AutoTrader will outperform any instant-offer platform, though it takes more time and effort.