Just for the sake of convenience here is a "lazy" estimated event ninja coupon cost compilation

9tl-naruto: 50000

rin-sasuke: 24000

edo-minato: 20800

sus-kakashi: 20800

edo-Hiruzen: 20700

6pt-naruto: 20000

edo-tobirama: 19600

ang-konan: 19200

izn-danzo: 18400

5ks-madara 17200

chk-kisame: 17200

8tl-bee: 15200

dpb-hidan: 14400

edo-deidara 14400

gdj-kakuzu: 12800

4kg-minato: 12300

edo-X-tails: 12000

uch-shishui: 12000

msk-man: 11200

jon-minato: 11200

heb-kushina: 9600

edo-nagato: 8800

anb-yamato: 8000

edo-sasori: 7200

anb-kakashi: 4800

edo-haku: 4800

drm-hinata: 4800

edo-asuma: 4400

anb-itachi: 3600

slr-sakura: 3200

2st-kushina: 960

2st-iruka: 840

1st-moegi: 75

PS: cost for 3* ninja unless stated otherways.

PS2: the edo-X-tails are (roshi, utakata, yagura and yugito nii)

PS3: all costs are a rough estimate based on Picklejuicy's coupon events topics.