If you bought the best 52 Mantle you could find, you'd need a lot more than 10K.
I'm not a big Mantle fan, but I think that card is probably your best "investment" card since it will be very sellable in the future, likely with a nice profit.
My opinion only : No other Topps/Bowman card is rare enough or desired enough to expect a high percentage gain, with a couple exceptions.
(I think 49B Jackie Robinson and 51 Bowman Mantle/Mays might qualify as good" investments" although I'm no expert in speculating!)
My 45 years of collecting are all just because I like collecting and the idea that some of my cards might "pay me back" someday is just a bonus, not a certainty.
There are a lot of pre-war cards that might qualify as reasonable answers to your question , given the right player and set.
For example, Cy Young, Babe Ruth, Ty Cobb and Lou Gehrig will always be desired cards. They are already pretty expensive, and some type cards of them are even rare. I wonder sometimes if the T206 And Goudey versions will remain the best types for these players in the future since they are NOT the rare ones...but if you start considering scarcer items like postcards and cabinets you might limit the interested audience in future years.
Excellent topic for the first non-football Sunday we have had in a while
Oops I wished I had noticed the section used...I still like the topic
