Daily rewards are prizes given for logging in each day. Currently, rewards are available for up to 150 days, and missed days don't affect them.
Prior to version 2.5, rewards were given on a 5-day cycle, and missing a day would reset the daily rewards.
The Amazon Underground Actually Free Version of the Daily Rewards works a bit differently. You earn gems daily, you get 3 for the first and second day, 7 for the third day, 3 for the fourth day and on the fifth day you get 10.
Oddly enough, the Pony, Decoration and Shop Prizes remained the same. But the other days go with the same pattern of gems earned: 3, 3, 7, 3 and 10. That means for every 5 days, you can earn up to 26 gems.
Game rewards players for every new day played with some reward.
Prior to version 2.5
It worked in a different way before - a five day cycle which was resetting if you miss a day. Also it featured rather boring rewards but yielded 3 in total for five days.
What you get
Random surprise rewards
Sometimes, the game pops up with a ad thing to give you a reward.
(the order for the September ones might be mixed up)