How many Coins do I need to redeem a reward?

The more Coins you redeem at once, the better value reward: 

$3 Reward: 3,000 Coins

$5 Reward: 5,000 Coins

$10 Reward: 9,500 Coins *

$25 Reward: 24,000 Coins *

$50 Reward: 47,000 Coins *

* When you save your Coins, you can redeem higher value rewards for less Coins

More reward options and amounts become available to you when you level up

See this article for more details