>>715356858
>buying
Stop, don't. Anyways, play 4, 5, 6, 7, 9, 12. As to what versions:
>4
PSP version. Includes the After Years, if you're willing to stomach it. Afterwards give the DS 3D remake a shot.
>5
GBA version with extra jobs.
>6
SNES version with JUST the GBA script patch. Ignore all other patches like "Uncensored Woosley Rose Re-balanced Hack ver. 2.0.9.2a" or whatever pointlessly autistic FF6 patch that has been going around the last 5 years
>7
PS1 original
>9
Original, or get the steam version but with the Moguri mod that irons out some things Square never fixed (like consistently allowing you to skip battle intros)
>12
Either the translated International Zodiac Job System ISO for PS2, or the official Zodiac Age version on Steam if you don't mind remastered visuals.

Avoid the Pixel Remasters of 1-6, they're scams. Remasters of 7-9 are dodgy at best, with 9 being the "best" but still needs to be modded. 10, besides being shit, has a fugly remaster made by chinks. 12 is a bit better, the newer visuals are a matter of taste, and the audio is still compressed to shit.