Which one should I play

>>27406434
Leaf green/fire red then heart gold/soul silver.

>>27406434
hgss or platinum

>>27406434
HGSS would probably be a good pick to see how it's changed a little bit while still seeing mostly mons you know.

Omega Ruby / Alpha Sapphire.

>>27406434
HGSS for something familiar
Black/White if you want to be out of your comfort zone, that game has no previous gen Pokemon throughout the whole game so you can't fall back on ol' reliable Oddish or Gyarados.
Platinum for a mix of both

>>27406434
You are X/Y's target demographic

>>27406700
Where could I buy HGSS that isn't super expensive though.

>>27406727
If you aren't opposed to emulators you can use Desmume.

>>27406727
I've found roms and an emulator that lets me play HGSS on my tablet. I'd highly recommend either game but you may want to see which game has what pokemon and pick accordingly.

btw: To get the rom on a phone or tablet you'll have to download it on a computer then put it on your tablet and/or phone. It's quite easy but I thought I'd let you know about that extra step.

>>27406434
If you do not mind the technological rollercoaster, this is what others have recommended to me:

Fire Red/Leaf Green (skip this if you want, remakes of the originals for moves/types/bug fixes/etc, same "story" as the originals but with the added fluff of the orange skippable islands)
HGSS
Emerald (Lots of folks dislike ORAS for various reasons, this one is up to you, ORAS is the current remake and such and will take getting used to when "downgrading" to the rest)
Platinum
White 1
Black 2 (semi continual storyline, many folks told me to "link up")
X n Y
Sun and Moon

HeartGold or SoulSilver if you can get a pokewalker.
Emerald otherwise.