The items placed in an auction don't generally have a market price - that's the point of the auction. So, there's a market price for gold. It wouldn't make se

The items placed in an auction don't generally have a market price - that's the point of the auction. So, there's a market price for gold. It wouldn't make sense to hold an auction for a 1oz block of gold because the price is known to everyone participating in the auction. On the other hand, say there's a 1oz rock taken back to Earth from a Mars mission. There's no market price and therefore no way to just sell it. The auction will find the True Value by auction - in Milgrom's case, going round by round and asking every bidder if they're willing to buy the rock at X price. In next round they ask every bidder if they're willing to buy it at 1.1X. So on and so on until there's only bidder left. To answer your question about valuing a used Tesla - a regression formula would work best, take the variables like mileage, features, color, etc. and find 30-40 used Tesla sales to create your formula.