[aljurgela]

Generally I would be reluctant to buy JUST for the hope of making $. Unless you get "lucky" with a low price (rare these days), you have substantially more transaction costs when selling through eBay or auction houses. Basically, if you buy a set for $10k today and you need to sell it tomorrow, you will need to get $11.5k just to break even on your fees.

If you are looking at a 10% return in a year, you need to identify something that will increase by 25% in a year. That is tough.

This said, if you want to look for the long term, I would go with something that is "relatively" undervalued. I could post again my thoughts on a "market cap" dynamic that I believe will balance in time, but we do not know when that time is. In general, my market cap philosophy goes as follows...

If you believe that Babe Ruth is the best player ever, the combined value of his cards should be worth more than anyone else. Of course this theory does not lack for holes (some of the more notable: availability of issue, entry price point can exclude certain would be purchasers - which is why companies have stock splits and Berkshire Hathaway has two classes of shares, beauty of the issue, etc.). But in general, if there were only 10 Ruth rookies and 10 Mantle rookies, you would expect the Ruth rookies to be "valued" more... right?

I have done some math on the # of graded cards of some key HOFers and my analysis generally leads me to the conclusion that certain players are over-valued and some are undervalued.

In general, players from the 50's (Mantle, Mays, Clemente, Aaron) tend to be over-valued from this perspective as do some "outliers" like Wagner and Plank (for obvious T206 reasons). Ruth is still cheap (at least the rookies) in my opinion as are a number of Negro Leaguers (I am very biased here, but the data supports it).

Sets are tougher to do this with. I would focus on ones that you can easily sell, if need be. The Cracker Jacks and T206 recommendations are "safe" from my opinion, but there are a number of cool options.

Best advice is get what you like as you may be "stuck" with it.

Best of luck.