Fruitomation/Assets/Scripts/Global/MoneyController.cs

using PashaBibko.Pacore.Attributes;
using Fruitomation.Game;
using UnityEngine;

namespace Fruitomation.Global
{
    [CreateInstanceOnStart] public class MoneyController : MonoBehaviour
    {
        private static MoneyController Instance;

        [SerializeField, InspectorReadOnly("Current Money")]
        private double InternalCurrentMoney = new();
        public static double Current => Instance.InternalCurrentMoney;

        public static void Add(double amount)
        {
            Instance.InternalCurrentMoney += amount;
        }

        public static bool CanBuy(double amount)
        {
            double val = Instance.InternalCurrentMoney - amount;
            if (val > 0f)
            {
                Instance.InternalCurrentMoney = val;
                return true;
            }

            return false;
        }

        private void Awake()
        {
            if (Instance is not null)
            {
                Debug.LogError("Cannot have multiple instances of [MoneyController]");
                return;
            }

            Instance = this;
        }
    }
}