The most expensive part of Stacie's project was the plywood that she painted with chalkboard paint. And the cute yardstick border - it cost her less than $5. She wrote up a tutorial for aging the yardsticks and putting it all together - find the link on her blog GingiberSnap.
If that blog name rings a bell it may be that you remember seeing it here on Ohdeedoh. Stacie is the creative force behind Gingiber where she sells prints, pillows and more for the modern nursery and she also shared Violet's nursery with us last year.
(p.s. I'll beat the commenters to the punch by adding that you may want to use dustless chalk for this project.)