Is there a messagebox class where I can just display a simple message box without a huge GUI library or any library upon program success or failure. (My script only does 1 thing). 
Also, I only need it to run on Windows.
You can also use the messagebox class from tkinter:
    from tkinter import messagebox
unless tkinter is that huge GUI you want to avoid.
Usage is simple, ie:
    messagebox.FunctionName(title, message [, options])
with FuntionName in (showinfo, showwarning, showerror, askquestion, askokcancel, askyesno, askretrycancel).
Python Message Box Without huge library dependency