Recently, resource trading has been regarded as a promising solution to deal with the resource scarcity of Internet-of-Things devices (IoTDs) to meet the performance requirements of sixth-generation (6G) networks. As 6G networks evolve to support diverse applications across multiple domains, trading of resources becomes essential to ensure efficient allocation and utilization of resources. However, ensuring transaction security and trust among traders and determining the best trading strategy for mobile virtual network operators (MVNOs) and IoTDs are challenging tasks. In this article, we first explore the resource trading literature and the types of resources IoTDs want to trade. Second, we investigate the trading strategies and pricing models for resource trading in 6G. Third, we present an artificial intelligence (AI)-native blockchain for multidomain resource trading (ABMRT) framework combining blockchain, AI approaches, and trading models that involve multiple MVNOs and IoTDs with varying service demands. The proposed framework is designed to support the diversified resource requirements of the IoTDs in a multidomain trading scenario. Finally, we discuss some challenges and future directions of resource trading in 6G networks.