The lucky board is one of the best event to spend for ftp. I spent 2600 coupon just now and, out of the exchange alone, got 25 charm pack.

I also got enough charm frags for another 2 packs alongside all the other random stuff on the board, including keys, threads, mood scrolls, magatamas etc.

And also 21 Lucky bags for completing rounds, which contained quite a good assortment of magatamas.

Now, personally it's becoming more meh for me, since I no longer need threads and magatama is hitting serious diminishing return. But if you are newish, this will provide a HUGE power boost.