Why does it not increase the value of Money in this script?

I'm assuming it's to do with the fact that you're missing a .Value from lines 4 and 11 after Useable. The if/then block on line 4 will never be true because you are comparing script.Parent.Useable, an Instance, to true, a boolean, which will never be equal. Instead, you need to check for the value.

Your code with fixes:

enabled = true

script.Parent.Touched:connect(function(hit)
    if hit.Parent:FindFirstChild("Humanoid") and enabled and script.Parent.Useable.Value == true then


        local player = game.Players:GetPlayerFromCharacter(hit.Parent)

        player.leaderstats.Money.Value = player.leaderstats.Money.Value + 100
        script.Parent.Useable.Value = false
        script.Parent.Parent.TQ1.Useable.Value = true
        wait(1)
        enabled = true
    end
end)