365 Pocket Prayers by Tyndale House Publishers (edited by Amy Mason)

I found this little prayer book at a local Goodwill. The simple prayers inside, while brief, are very powerful and insightful. As someone who enjoys prayer books (Book of Common Prayer, Larger Catechism, Prayers at Sea, and more) this was a great pickup for me. Another benefit is the topical index in the back which is great for those days where you need a little encouragement.