Amazon offers its Amazon Prime members the Totally Bamboo 3-Piece Cutting Board Set for $12.99 with free shipping. (Non-members can spend $25 or more to qualify for free shipping; otherwise, shipping costs $6.76.) That's the lowest total price we could find for a similar set by $9. It features 6" x 8", 8.5" x 11", and 9.5" x 13" boards.
Amazon Prime membership is $79 per year; however, Prime is free for college students for six months, and free for parents and caregivers for three months. (Note that currently there's a waitlist for Amazon Mom.)