In this chapter we describe MAGNET, a tuplespace-based framework for dynamic trading of services addressing the needs of application in frequently-changing mobile environments. In addition to user-customized trading, MAGNET enables adaptation to a changed environment by supporting constant monitoring of selected information, mobile adaptability and scalability. In addition to presenting the MAGNET architecture and demonstrating its key features, this chapter brings an overview of dynamic trading in mobile systems and presents a theoretical framework for reconfigurability and adaptability. Firstly, we argue that a key characteristic of mobile applications is the need for up-to-date location-dependent information, and adaptability to local configurations while the physical location of users changes frequently. Then, we discuss MAGNET – a model for dynamic trading and its implementation using a tuplespace paradigm. Further, we provide an extensive description of the support for information monitoring, dynamic adaptability and scalability. Presented features are illustrated on a typical real-world scenario – adaptable resource allocation.