There wouldn't be a measure for actual price other than the one set by the seller/buyer. Stock exchanges set prices based on the difference of value.

No one is suggesting that every THING of value be forced to be equal. Things differ in value to different people, hence allowing for mutually beneficial exchange. You're shifting the example to be something ridiculous and then arguing against that. People having equal amounts of wealth does not inhibit the economy. That's the argument you contended against to begin with here.