Lucky board comes usually at the first week of a month. For 2k coupons you can get 100 dices, which will give you somewhere between 500-750 points. I think the cheapest ninja Ive seen was Pain Gakido, which costed 10points/frag (so 800/ninja, which is 800/5*20= 3200 coupons with the lowest possible point roll (no function grid)). There was also sage jiraya for 13 points and danzo around 25 points.
I dont know what team u r using, what ninja do u have or need, so the best bet is wait for a mission mobilisation event, which gives away up to 1050 points for free (then u can buy 10 points for 20cp in the shop) and get free ninja frags there. Same rule applies to any other event in which u can redeem ninja frags basically for free. Then, once u r close, u can consider getting the rest frags for coupons. Remember, that every ninja, even those which were viable in 1.0 and are long forgotten now are still expensive if u dont spend. Getting a ninja from scratch during free events takes about 1-2months (for example sage naruto).
Also smart (but time consuming) method is hoarding coupons for lucky board, but spending them ONLY when theres a ninja in redeemable that u want, not just some random that u will never use.
tl;dr u wont get a good ninja for 2k coupons.
This post was last edited by Zathroth at 2017-7-21 05:21