The Alamo codes typically post flawlessly for me. I book directly via the Alamo site, logged in with my Alamo ID.
Just booked one today for early Feb. I usually don't pay attention to the "40% off" part, knowing it hardly ever works that way. But in this case, I had a rental that was pricing at $21/day with my best other codes....and $12(!) with the WN code.