There’s a daily bonus puzzle every morning where you can earn coins to buy extra puzzles or hints. You used to be able to randomly earn 5, 7, or 10 coins per set of 3, with 9 bonus puzzles a day for a daily minimum of 9 cousins. It was truly random. A hint cost more than you would generally get in one day, but only a little more. And, you could try to store up coins to buy bonus puzzles once you’d completed all the free ones.
Then they changed it to 3, 5, or 10 coins, and changed the algorithm as well. I have yet to earn more than 16 coins a day for weeks now. A hint costs 30 coins so if I’m only getting 9 per day (most days now), it is not worth playing anymore. And the puzzles are hard enough now that I will be stuck for days if I don’t use hints. It’s sucked all the joy out of this game. Do yourself a favor and find a different pangram game - there must be plenty out there.