Bukkit

MMAPI.setMoney(Player p, String money, String market)
sets the player p's money as money for the market market

MMAPI.getMoney(Player p, String market)
returns player p money from market as an int

MMAPI.defaultSell(Player player, String market, int price, ItemStack item)
if player has the item in his hand, then it will take away the item from him and give them price in market

MMAPI.defaultBuy(Player player, String market, int price, String cmdToExecute)
checks is player has enough money from market, then executes the cmdToExecute from the terminal and takes away price

		int money = MMAPI.getMoney(player, market);
		if (something isnt correct. maybe the item in his hand isnt there or something) {
			player.sendMessage(ChatColor.RED + "Something Isnt Correct");
			return;
		} else {
			
			int moneyy = money + price;
			
                        //this is where you would do something
			
			MMAPI.setMoney(player, moneyy + "", market);
			
		}

		int money = MMAPI.getMoney(player, market);
		if (money < price) {
			player.sendMessage(ChatColor.RED + "You do not have sufficient funds!");
			return;
		} else {
			
			int moneyy = money - price;
			
		        //do something here
		
			MMAPI.setMoney(player, moneyy + "", market);
			
		}