You may still find many Rare comics available on the market and anyone with sufficient funds can own one. Most for $50 and less will be from the 60's and 70's era. An example of this would be the World's Finest #185, which featured the Galactic Gamblers, in addition to Batman and Superman. This one is from DC comics had been published in 1969 and it is now selling for $30. There is also the Adventure Comics Presents, DC comics The New Supergirl published in 1970 now with a selling price of $18.