Walmart offers the Stalwart Adjustable Under Sink Shelf Organizer Unit, model no. 82-50702, for $11.97. (Amazon charges the same with free shipping for Prime members.) Opt for in-store pickup to dodge the $5.97 shipping charge. That's tied with our mention from a week ago and the lowest price we could find today by $3. It features an adjustable width from 17.75" to 32".