So Far we've only seen Jonin Minato in Fateful Choice, and TIme-Limited shop.

Fateful choice event- 10-13.5k coups is about the average for most people. Roughly 200 coups per frag. You need a ton of luck to get him for 10k.

TIme-Limited Shop- Priced at around 16k (INGOT Only) so keep that in mind. Sweeps count but hardly enough points to finish him unless you would be 2-5 frags shy at that point in time.

If they manage to put him in general mobilizations, at the same points redeemable as Masked Man, you can snag him for around 12k. For Masked man you were able to redeem 9-10 frags for the free over the course of the event. This would currently be the most cost efficient unless you are spending ingots for time limited. And even then that is a bit pricey.