-- client side

addEventHandler( "onClientGUIClick", resourceRoot,
function()
    if (source == GUIEditor.button[1]) then -- The button to buy
        guiSetVisible(GUIEditor.window[1], true) -- The window to buy
        showCursor(true)
    elseif (source == buyButton) then -- add your button to buy
        buyFish()
    end
end)


function buyFish()
    local money = getPlayerMoney(localPlayer)
    if (money >= 300) then
        outputChatBox("You have bought a fish food.")
        triggerServerEvent("buyFish", resourceRoot)
    else
        outputChatBox("You don't have enough money.")
    end
end


-- server side

function buyFish()
    takePlayerMoney(client, 300)
end
addEvent("buyFish", true)
addEventHandler("buyFish", root, buyFish)