I like to play highly mobile champions and im wondering what champion i should i buy first
ahri
ezreal
fizz
other (please specify)

I like fizz but he seems more of a counterpick at this point. Ez is really good if you can land your skill shots

Ahri is super fun. I think you might also like Kennen - he's also fun

lol i already own kennen. just looking for a new champ. might get ahri first

Kassadin is one of my favorites.

In the order of what you provided, Fizz, Ahri then Ez. My preference.

haha YAY FIZZ IS ON SALE

Fizz is super fun, but a somewhat dangerous pick IMO. Ahri is great. One of my favourite champs and probably one of the best mid-laners if her popularity is anything to go by. She's hard to play really well though, as is Ezreal.

Ahri:

• 2 Abilities are Skill Shots
• Only mobility is her ultimate. Usable 3 times within the space of a few seconds.

• 3 Abilities are Skill Shots
• Short Cooldown teleport

• Dash to Enemy Champion
• 1 or 2 use Jump which makes you Untargetable which also slows
• Ultimate is a skill shot

Riven, or my favorite, Nidalee. Both super mobile and high damage --- I play AD nid.