bought 111 packs here (to get 37 fragments of the summer youth sai) and didn't get him or sasori, just magatamas.

If you don't own Summer Youth Sai, first you should get it since the price is pretty low (2600-3000 coupons, depeding on how many missions you are able to accomplish).

The price for charm packs is not really appealing. In konoha shop the deluxe charm pack (that is like 50 charm packs) costs 4000 coupons (so 80 coupons per pack). In treasure of the sage you can get a 30%/40% discount and get them with 87.5/75 coupons per pack.

So no, is not worth it, unless you want to test your luck with Ay. In average seems you get 1 level 4 magatama every 10 packs (got 11 of them in 111 packs).