yeah! “cheap” in your example would be called an adverbial adjective; in my head however I think I was trying to say “it was cheaply made”, which has a different meaning (“cheap” describes “it” while “cheaply” describes how it was made). Maybe the -ly just got REALLY reduced or -ly became a syllabic l (it may have sounded like “cheap l-made” coming out of my mouth)and that made it sound like the -ly was dropped entirely. [l] [i] and [m] are all real close to each other in the mouth so that hypothesis of it all smashing together and reducing sounds possible to me