I understand your feelings about purchasing films that may "collect dust." However, I did see both Mr. Moto sets at Costco selling for, I believe, $31.99 each just last week, if this helps.
The Mr. Wong films are great. The one with Luke as Mr. Wong is a bit of a stretch after having seen the others, but well done & fun to watch. I especially like the scenes with Lee Tong Fu fussing about.