Just a question first.
We just had him in event, like a dozen of people got him. You could get him from like 1-300 box maybe.
So tell me, why do you want to try getting him now?

He cost 3200 from black market and cost like 10k+++ from seal and will be added in the shops later.

I tried, opened around 100 boxes and no itachi

Yeh he shows up in exchange shop later on so it depends on how much you want him. You should have stuck with Boxes if you wanted him, from what i saw he came roughly every 200-500 boxes, but even without him boxes had decent return on coupons from ''junk'' items.

Next best option would be black market, he would be 3200 - 4800 coupons from there since he is 40/60 per frag. Seal scrolls is well, a gamble, you could get him early or you could not get him even after few hundred scrolls.

Itachi will be one of the first shop update ninjas to be added, Just hold on till then. Shop update is fairly soon also.

I see.
Well if you are fine with slowly getting him, then blackmarket + survival treasure combo can help with that.
Personally the ninjas I see the most are Jigokudo, Itachi and Choji dad in the cards and I got 12 frag so far from him.

Other way is Arena coins, I think we gonna get ninja update in max a few more week, so start saving now if you didnt do it.

And the third way is the Kage Treasure. He supposed to be normal 3 star ninja here who possible to be drawn with 10 seal. But we dont know when we get this treasure.

Im ready for him. :@

The reason Itachi is so easy to get is because Susanoo Itachi is coming soon after and he becomes obsolete.

Susanoo version is immune to combos and debuffs. He's way better.