Restructured the project structure back to the way it was, there's no reasonable way to split the modules

src/NadekoBot/_common/Gambling/Betflip/BetflipGame.cs

@@ -0,0 +1,33 @@
+namespace Nadeko.Econ.Gambling;
+
+public sealed class BetflipGame
+{
+    private readonly decimal _winMulti;
+    private static readonly NadekoRandom _rng = new NadekoRandom();
+
+    public BetflipGame(decimal winMulti)
+    {
+        _winMulti = winMulti;
+    }
+
+    public BetflipResult Flip(byte guess, decimal amount)
+    {
+        var side = (byte)_rng.Next(0, 2);
+        if (side == guess)
+        {
+            return new BetflipResult()
+            {
+                Side = side,
+                Won = amount * _winMulti,
+                Multiplier = _winMulti
+            };
+        }
+
+        return new BetflipResult()
+        {
+            Side = side,
+            Won = 0,
+            Multiplier = 0,
+        };
+    }
+}