Here is the Pottery Barn version:
(source Pottery Barn Kids)
So I started googling and found an amazing website called Knock-Off Wood by Anna White. Anna is a genius when it comes to making anything to do with wood. She gives amazingly detailed instructions on how to make these adorable shelves on her website.
I cannot tell you how easy these were to make and how nice they look!
I went to my local Home Depot and found precut pine wood in the perfect length of 36 inches (they also had 24 inch ones too)!!! These pieces worked out cheaper than the longer pieces that I would have had to cut! The only cutting I had to do was for the two side pieces and if you don't want to do the curved cut, you can have Home Depot cut a squared edge for you for free!
I won't bore you with the details on how I made these because Anna does an amazing job but I will tell you I made a slight modification to the top guard piece. We flipped it so more books could fit in the shelf. Either way works but this was our preference.
As you know, I live in Canada, so the wood cost a little more than Anna White's version. The grand total for this each shelf was approximately $10 for the wood and $2.50 for the spray paint. I could have saved a few dollars by using primed MDF but we would have had to do more cuts. I was overjoyed with the end result and pretty happy with the price, especially when Pottery Barn is charging $49!