Im not sure what is wrong with this script which is Enabling a GUI when touched, [FE]?

###You can't access the PlayerGui from the server. You'll need a RemoteEvent for that.

###You're getting ServerStorage is not a valid member of DataModel because ServerStorage is server-side only, it does not exist on the client world. Switch to ReplicatedStorage to fix. Now, there is a lot bad I am seeing in your code. The first thing being: You're checking the requirements on the client, which gives the client power. They can reduce the requirements. Always have the server do checks. Second thing, you're handling the cloning locally, which will only appear for one player. Handle that on the server.

--Server script
local ReplicatedStorage = game:GetService("ReplicatedStorage")
local cloneTool = ReplicatedStorage:WaitForChild("CloneToolEvent")
local checkPrice = ReplicatedStorage:WaitForChild("GetPrice")

cloneTool.OnServerEvent:Connect(function(plr, toolName, sticksRequired)
    if plr.Database.Value_Inv.Stick_Value.Value >=  sticksRequired then
        -- I'm checking if sticks required is enough, on the server.

        local clone = ReplicatedStorage.Storage.Swords[toolName]:Clone()
        clone.Parent = plr.Backpack
        clone:Clone().Parent = plr.StarterGear
    else
        -- Do code if the condition is false
    end
end)

local GetPrice

GetPrice = function(player, toolName)
    return ReplicatedStorage.Storage.Swords[toolName].Price.Value
    -- I put an IntValue named price inside the sword.
end

checkPrice.OnServerInvoke = GetPrice

###Local code:

local ReplicatedStorage = game:GetService("ReplicatedStorage")
local price = ReplicatedStorage.GetPrice:InvokeServer("DiamondSword")
local cloneTool = ReplicatedStorage:WaitForChild("CloneToolEvent")

script.Parent.MouseButton1Click:Connect(function()
    cloneTool:FireServer("DiamondSword", price)
end)

###Just an example. Hope it helped.