How do I make leaderstats change when a brick is touched?

Is it an obby game? If it is, make sure all checkpoints (the stages) are all named according to their order (number of stage). The first stage must be a SpawnLocation, make sure AllowTeamChangeOnTouch is turned off and Neutral is turned on.

I recommend adding Stage value in the leaderstats too. The DataStore script should be looking like this:

local DataStoreService = game:GetService("DataStoreService")
local DataStore = DataStoreService:GetDataStore("MoneyStats")

local function create(player)
    local userId = player.UserId
    local key = "Player_" .. userId

    local folder = Instance.new("Folder", plr)
    folder.Name = "leaderstats"

    local currency = Instance.new("IntValue", folder)
    currency.Name = "Money"

    local stages = Instance.new("IntValue", folder)
    stages.Name = "Stage"

    local data
    local success, result = pcall(function()
        data = DataStore:GetAsync(userId)
    end)

    if success and data then
        currency.Value = data[1] or 0
        stages.Value = data[2] or 1
    else
        print("Error!" .. result)
    end
end

local function save(player)
    local userId = player.UserId
    local key = "Player_" .. userId
    local leaderstats = player:FindFirstChild

    local DataToSave = {
        player.leaderstats.Money.Value
        player.leaderstats.Stage.Value
    }

    local success, result = pcall(function()
        DataStore:SetAsync(userId, DataToSave)
    end)

    if success then
        print("Success!")
    else
        print("Error!")
        warn(result)
    end
end

game.Players.PlayerAdded:Connect(create)
game.Players.PlayerRemoving:Connect(save)
game:BindToClose(function()
    if game:GetService("RunService"):IsStudio() then return end

    for _, plr in pairs(game.Players:GetPlayers) do
        save(plr)
    end
end)

Then, you create another script in ServerScriptService for the checkpoints/stages, name it "CheckpointSystem".

game.Workspace.ChildAdded:Connect(function(char)
    local plr = game.Players:GetPlayerFromCharacter(char)
    if plr ~= nil then
        local leaderstats = plr.leaderstats
        local stage = game.Workspace.StagesFolder:FindFirstChild(leaderstats.Stage.Value)
        if char:FindFirstChild("HumanoidRootPart") then
            char.HumanoidRootPart.CFrame = char.HumanoidRootPart.CFrame + Vector3.new(0,3,0)
            wait()
            char.HumanoidRootPart.CFrame = stage.CFrame + Vector3.new(0,3,0)
        end
    end
end)

And lastly, this code will function when a player touches a checkpoint, so you put this script in ALL CHECKPOINTS! (except for the first checkpoint)

--This script must be in a "Script", not in a "LocalScript"
local Players = game:GetService("Players")
local part = script.Parent

local function onTouched(hit)
    if hit and hit.Parent and hit.Parent:FindFirstChild("Humanoid") and hit.Parent:FindFirstChild("HumanoidRootPart") and Players:GetPlayerFromCharacter(hit.Parent) then
        local plr = Players:GetPlayerFromCharacter(hit.Parent)

        local ls = plr:FindFirstChild("leaderstats")

        if ls.Stage.Value < tonumber(part.Name) and ls.Stage.Value == ((tonumber(bricklol.Name)) - 1) then
            ls.Stage.Value = tonumber(bricklol.Name)
            ls.Money.Value = ls.Money.Value + 100
        end
    end
end

part.Touched:Connect(onTouched)

Hope this helps! This took me hours to type this myself and let me know if there are errors or simple mistakes I did. Have a good day! ^^