Partially revert "Stop using pre-apoc price as a fallback for postapoc price" (#82284)

Author: John-Candlebury

src/item_factory.cpp

@@ -386,6 +386,10 @@ void Item_factory::finalize_pre( itype &obj )
         obj.category_force = calc_category( obj );
     }
 
+    // use pre-Cataclysm price as default if post-cataclysm price unspecified
+    if( obj.price_post < 0_cent ) {
+        obj.price_post = obj.price;
+    }
     // use base volume if integral volume unspecified
     if( obj.integral_volume < 0_ml ) {
         obj.integral_volume = obj.volume;
@@ -4069,7 +4073,7 @@ void itype::load( const JsonObject &jo, std::string_view src )
     optional( jo, was_loaded, "volume", volume );
     optional( jo, was_loaded, "longest_side", longest_side, -1_mm );
     optional( jo, was_loaded, "price", price, not_negative_money, 0_cent );
-    optional( jo, was_loaded, "price_postapoc", price_post, not_negative_money, 0_cent );
+    optional( jo, was_loaded, "price_postapoc", price_post, not_negative_money, -1_cent );
     optional( jo, was_loaded, "stackable", stackable_ );
     optional( jo, was_loaded, "integral_volume", integral_volume, not_negative_volume, -1_ml );
     optional( jo, was_loaded, "integral_longest_side", integral_longest_side, not_negative_length,

src/itype.h

@@ -1515,7 +1515,7 @@ struct itype {
         units::money price = 0_cent;
 
         /** Value after the Cataclysm, dependent upon practical usages. Price given is for a default-sized stack. */
-        units::money price_post = 0_cent;
+        units::money price_post = -1_cent;
 
         // TODO: Add some very basic unweildiness calc for non specified to_hit?
         int m_to_hit = -2;  // To-hit bonus for melee combat, see GAME_BALANCE.md#to-hit-value