If you have a Jonin medal, you can get 10 free. But if you want to finish this without one, you have to pay 50 coupons.

For players who doesn't have a Jonin Medal, completing that Mission is impossible .. Non-Medal Users only have 5 Free Attempts per day while Medal Users have 10 i guess, from what other people say, dunno since i haven't activated a Medal ..

If you wanna finish that 10 Times Ranked Arena, you'll need to pay Coupons per attempt and each attempt increases the prize, buying first attempt will cost you 10 coupons, 20 coupons for the next, and i'm not sure maybe 30 for the 3rd and so on and so forth ..

they should just let space-time fights count for this so f2p players have the same chance it finishing this mission, or make ranked count for 2 fights if the person doesnt have a medal