added botcut setting to gambling.yml in which you can configure shopcut for now (how much money the bot takes when something is sold in the shop)

src/NadekoBot/Modules/Gambling/GamblingConfig.cs

@@ -42,6 +42,9 @@ public sealed partial class GamblingConfig : ICloneable<GamblingConfig>
 
     [Comment("""How much will each user's owned currency decay over time.""")]
     public DecayConfig Decay { get; set; }
+    
+    [Comment("""What is the bot's cut on some transactions""")]
+    public BotCutConfig BotCuts { get; set; }
 
     [Comment("""Settings for LuckyLadder command""")]
     public LuckyLadderSettings LuckyLadder { get; set; }
@@ -75,6 +78,7 @@ public sealed partial class GamblingConfig : ICloneable<GamblingConfig>
         Decay = new();
         Slots = new();
         LuckyLadder = new();
+        BotCuts = new();
     }
 }
 
@@ -384,4 +388,17 @@ public sealed partial class BetRollPair
 {
     public int WhenAbove { get; set; }
     public float MultiplyBy { get; set; }
+}
+
+[Cloneable]
+public sealed partial class BotCutConfig
+{
+    [Comment("""
+             Shop sale cut percentage.
+             Whenever a user buys something from the shop, bot will take a cut equal to this percentage.
+             The rest goes to the user who posted the item/role/whatever to the shop.
+             This is a good way to reduce the amount of currency in circulation therefore keeping the inflation in check.
+             Default 0.1 (10%).
+             """)]
+    public decimal ShopSaleCut { get; set; } = 0.1m;
 }

src/NadekoBot/Modules/Gambling/GamblingConfigService.cs

@@ -182,5 +182,13 @@ public sealed class GamblingConfigService : ConfigServiceBase<GamblingConfig>
                 c.Version = 6;
             });
         }
+
+        if (data.Version < 7)
+        {
+            ModifyConfig(c =>
+            {
+                c.Version = 7;
+            });
+        }
     }
 }

src/NadekoBot/Modules/Gambling/Shop/ShopCommands.cs

@@ -283,8 +283,8 @@ public partial class Gambling
             }
         }
 
-        private static long GetProfitAmount(int price)
-            => (int)Math.Ceiling(0.90 * price);
+        private long GetProfitAmount(int price)
+            => (int)Math.Ceiling((1.0m - Config.BotCuts.ShopSaleCut) * price);
 
         [Cmd]
         [RequireContext(ContextType.Guild)]