Price lists let you offer advanced variant-level price overrides based on customer groups. Visitors to your store see the same products, but are shown different prices based on the group they belong to.
For example, a wholesale merchant might offer standard (retail) pricing to all visitors of their store, but also offer special discounted pricing that only certain customers can see and access.
This feature is limited to Enterprise plans.
For more information, view the BigCommerce documentation here.