Use reactions as data
Place a small quantity at a cautious price and observe the first unambiguous customer response. Raise or lower one step, then test again. Changing several items and perks at once hides which variable produced the result.
Protect opportunity value
A rare relic may be worth more as part of a backpack synergy or future objective than as immediate shop inventory. Keep notes by relic and current version, but treat old price tables as starting hypotheses. Shop upgrades, special events, and balance changes can alter demand, so the live reaction remains the final signal.