Your miss understanding me.
Lets take your example a 50/50/50 gun of some description.
Lets say for example its a 50% Fire rate 50% Damage 50% accuracy Famas.
what I am suggesting is Harry will track this sale and put it into a data base. if this were to happen say 10 more times we could get an average price (if no one is messing with the system).
Of course this would be rare to be sold with EXACLTY those stats so we would put them in brackets with TOTAL percentages with the stats. so the gun in question would be a 150% famas with FR/DMG/ACC. We would ideally put them in say a 155% (top percentage) to 145% with 10% deviations. so ANY famas with 145%-155% total stats with DMG/FR/ACC sold in that would be grouped together, the average price sold found and splurted out as the base line. repeat this for all guns and ALL stats and we have a comprehensive gun price guide. For that one combo alone…
This way would include inflation as it is factored into the equation, the new weapons would slowly get its average prices with the stat ranges. and maybe help people get price ranges.
Prices are decided by the seller. But there is a general consensus if something is being sold for too much.
granted to get these results would take a long time to get