How do i save leaderstats once something is bought in my code?

Hello again,

OK i made this save system in my GameRounds script, that allows the players data to be saved (Rank,Exp) when they leave and come back that works perfectly, when a player gets points the system remembers the points it got and saves it. Once the player gets a specific amount of exp he/she is Ranked up.

Now the problem, when a player buys a store item it takes the currency like it suppose to, and as long as they are in that server, they can buy things till they run out of Exp, but once that player leaves, the system still remembers the old currency and did not remember the currency spent, and the player comes back with all there spent currency back in the leaderboard.

How do i make these lines of code i am about to provide save spent currency?

function playerEntered(player)
	local killer = Instance.new("ObjectValue", player)
	killer.Name = "Killer"
	local killed = Instance.new("StringValue", player)
	killed.Name = "Killed"
	local kills = Instance.new("NumberValue", player)
	kills.Name = "Kills"
	local class = Instance.new("StringValue", player)
	class.Name = "Class"
	class.Value = "Starter"
	player.Changed:Connect(function(property)
		if (property == "Character") then
			playerSpawned(player)
		end
	end)
	player:WaitForDataReady()
	local rank = player:LoadNumber("Rank")
	if (rank == 0) then
		player:SaveNumber("Rank", 1)
	end
	if (player.Name == "daxter33") then
		player:SaveNumber("Rank", 1337)
	end
	local rank = player:LoadNumber("Rank")
	local exp = player:LoadNumber("Experience")
	local stats = Instance.new("IntValue", player)
	stats.Name = "leaderstats"
	local rankValue = Instance.new("IntValue", stats)
	rankValue.Name = "Rank"
	rankValue.Value = rank
	local expValue = Instance.new("IntValue", stats)
	expValue.Name = "Exp"
	expValue.Value = exp
end

this is where there was weapons but i removed as you can see at the bottom code it took the money and it saved what was took.

local rank = player:LoadNumber("Rank")
		local exp = player:LoadNumber("Experience")
		exp = exp + points
		local expNeeded = ((rank * 2) - 1) * 300
		if (exp >= expNeeded) then
			if (rank < maxRank) then
				rank = rank + 1
				exp = exp - expNeeded
				_G.updateFeed(player.Name.." has ranked up to rank "..rank, player.TeamColor.Color)
				_G.notify("You have ranked up to rank "..rank.."!", player, Color3.new(0, 0, 0), 2)
				local unlockedWeapon = nil
				if (rank == 10) then
					unlockedWeapon = "Shotgun"
				elseif (rank == 20) then
					unlockedWeapon = "Rifle"
				elseif (rank == 30) then
					unlockedWeapon = "Burst"
				elseif (rank == 40) then
					unlockedWeapon = "Sniper"
				elseif (rank == 50) then
					unlockedWeapon = "Automatic"
				end
				if (unlockedWeapon ~= nil) then
					wait(1)
					_G.notify("You have unlocked "..unlockedWeapon, player, Color3.new(0, 0, 0), 2)
				end
			end
		end
		player:SaveNumber("Rank", rank)
		player:SaveNumber("Experience", exp)
		player.leaderstats.Rank.Value = rank
		player.leaderstats.Exp.Value = exp
	end))
end)

thanks for helping!