I'm looking for an AP mid that costs no more than 3150 IP. My current picks are Mordekaiser and Leblanc, and in case you're wondering, I have Akali. Who should I choose?

It's a good idea to have all the champions that cost 450 and 1350 just so you can trade them when you hit 30 for ranked.

If you have any interest in Annie, Ryze, Veigar, Evelynn or Morganna they are safe buys which you could still use down the road even if you dislike and don't end up playing them.

Do you mean you have those or are considering getting those? Sry, English not mother tongue.

Mordekaiser is extremely easy to play and generally auto-wins mid lane when there is no jungle interaction.

Leblanc roams a lot and is good for players who want to put fear in all lanes at once but is harder to play than Mordekaiser.

Im not sure on the price, but Lux is a pretty good mid laner. She has a snare, AoE, hit after spell +damage passive, one of the best shields, and a very long range laser that can go 1/4 of the map. She might be a little pricier, but you might want to consider her.

I don't recommend Leb for beginners. I failed very hard in ARAMs wtih her because she is so ****ing micro intensive, in my eyes.

Did you think about Annie? Or Veigar? Those are the I-unload-my-****-and-GTFO-quickly champs.

Morde and Leb are about lane control, the first usually built rather tanky and the latter killing squishies (low HP targets) quickly.

Lux...I recall my second or first game with her ended up 0 15 5, don't ask me why, I didnt even got flamed down for that one.

Leb vs Morde I would definitivly recommend mordekaiser to you, this is being said without maining one of those. He should be rather strong at your levels.