Add a "structure sold" notification.

OpenRA.Mods.Common/Activities/Sell.cs

@@ -48,6 +48,8 @@ namespace OpenRA.Mods.Common.Activities
 			if (showTicks && refund > 0 && self.Owner.IsAlliedWith(self.World.RenderPlayer))
 				self.World.AddFrameEndTask(w => w.Add(new FloatingText(self.CenterPosition, self.Owner.Color, FloatingText.FormatCashTick(refund), 30)));
 
+			Game.Sound.PlayNotification(self.World.Map.Rules, self.Owner, "Speech", sellableInfo.Notification, self.Owner.Faction.InternalName);
+
 			self.Dispose();
 			return false;
 		}

OpenRA.Mods.Common/Traits/Sellable.cs

@@ -26,6 +26,10 @@ namespace OpenRA.Mods.Common.Traits
 		[Desc("List of audio clips to play when the actor is being sold.")]
 		public readonly string[] SellSounds = { };
 
+		[NotificationReference("Speech")]
+		[Desc("The audio notification type to play.")]
+		public string Notification = null;
+
 		[Desc("Whether to show the cash tick indicators rising from the actor.")]
 		public readonly bool ShowTicks = true;