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!