You know what a product is actually worth by thinking hard about what use or pleasure you'll get from it. If you're currently trying to deduce what things are w

You know what a product is actually worth by thinking hard about what use or pleasure you'll get from it. If you're currently trying to deduce what things are worth from their prices, you're already getting very wrong answers -- price-setting is a complicated business involving lots of psychological trickery. Sometimes you can sell more units of a product by increasing the price, precisely because lots of people use the "what it costs is what it's worth" heuristic; you can often sell more of product X at $P without changing either X or P, just by introducing a new super-expensive premium version of X that costs $(10*P); etc.