Ikea is growing its resale business. It’s attracting bargain hunters and design nerds.

Your old Ikea bookshelf is part of a growing secondhand market.

Ikea has spent five years growing its buyback and resell division, which pays customers for their old Ikea-brand furniture in store credit and resells it at the chain’s stores.

In September, buyback and resell will be available in every full-format US Ikea store when the retailer starts offering the option at its Brooklyn store, said Bryan Walker, country product quality manager for Ikea US.

For shoppers, buying secondhand has long been a way to save money across a range of products. It’s also become a bigger business over the last several years, from side-hustlers selling clothes…