I think the Liturgy of the Hours is a particularly beautiful way to bring a peaceful rhythm and focus to your day. I go through time periods where I pray it faithfully and time periods where I drop it all together, but I always find that picking it up is a peaceful and comforting thing.
Or, if you prefer more bookish options…
Night Prayer (one volume – under $10) is a really easy place to start for beginners. This is a slim volume with just the Night Prayer from the Liturgy of the Hours. This is probably the simplest portion of the Liturgy of the Hours to learn, and it is very beautiful and comforting.
Christian Prayer (one volume) is a less expensive (about $25) and slightly less intimidating place to start. It’s perfect if you are planning on praying some combination of Morning Prayer, Evening Prayer and Night Prayer. Because it’s more compact than the four-volume set, it can involve a little more page turning.
The Liturgy of the Hours (four-volume) is a pricier (about $150 for the set) place to start, but more thorough. There is a volume for Advent & Christmas, one for Lent & Easter and two for Ordinary Time. I think this set has an advantage over Christian Prayer in being easier to use for the Office of Readings (generally said before Morning Prayer), which includes additional readings from Scripture, the Fathers of the Church and the Saints.