So far in the last 60 games, i couldnt get a 3 games streak where i didnt have at least 1 leaver / afk. Enemy team never has those. If they do, its in game where i have them too. But i have played so many 4v5s, but never a single 5v4. I check enemy match histories, and i see no leavers in 3 pages of their games, so clearly they are doing something right.

How to buy coins from here?

Hmm, store maybe?