I am joining for your advent calendar. I don't want to miss out any free stuff. But I am assuming that the rain happens in the chat? Who is eligible to participate on that? Do i have to bet on the games first or is it only for active (talking) people? Or maybe both?
Yes, rain comes in multiple forms but the most common one is free and paid. Free, is just basically you can join without any wagering requirements while the paid ones like avalanches and tornadoes have wagering requirements before you can join.
And more you claim more you need to wager to be able to claim again! I lost some deposits, and I was just claiming prizes for 2 days, from daily and chat, and I had more than 10 chests. After some time I couldn't claim any coins in chat and I couldn't claim daily, I needed to wager 90k coins to be able to do that again (I assume because I claimed around 5k in free coins in 2 days).
For claiming you need to wager, more you claim more you need to wager! Anyway when you reach your limit and try to claim you will get a message how much you need to wager to be able to claim!
I can't say I had luck from all my chests (I am +40 level), I saw people winning a lot, but I didn't get more than +200 coins per chest, sometimes it was +50coins only!