I really believe that if purchased smartly and treated like an investment that a lot of money could be made by buying toys, video games, other collectibles, and putting them up....
I remember at one point a local game store was using a Nintendo 64 as a door stop. Crappy used one from gamestop cost 79.99 now - boxed is well above msrp way back when.
Scalpers and discipline make it difficult for me, and space.
A lot of thought has to be put into it. It'd probably take 30 years before a sealed copy of Burnout Remastered amounted to anything close to what msrp cost but with some research and a little luck who knows.