The Greatest Hits label has long been an integral part of the game library for Sony's consoles. It was started to give elite status to best selling games on the PlayStation, PlayStation 2, PlayStation 3, and PlayStation Portable, and since the program began in 1997, there have been over 580 Greatest Hits titles across all four platforms.
When a game became Greatest Hits, two things would happen; the game would drop in price (usually between $19.99 and $29.99), and the collector's value of the original "Black Label" version would begin to rise. While it's not applicable to all games, RPG's in particular like Final Fantasy VII enjoy a noticeable difference in price when comparing the "Green Label" and "Black Label" versions.

Consider the
Final Fantasy Anthology for PS1. The original printing had a black label, the old-style white ESRB rating, and listed Squaresoft as the publisher. The new print, which is still in production brand new, has a green label, the new-style black ESRB rating, and lists Square-Enix as the publisher.