The present invention provides an interchangeable shoe footbed cartridge system. The system includes a footbed such as a midsole, insole or a sockliner. A cartridge is inserted into or otherwise attached to the forefoot section of the footbed. Multiple cartridges of varying depths, widths and/or lengths may be provided. The wearer can select a cartridge to achieve a desired fit. Because right and left feet may be of different sizes, different cartridges may be chosen for each foot. Furthermore, the user may swap cartridges depending upon different conditions, or to change the stiffness of the cartridge. Additionally, a slipcover having a stretchable portion may be placed over the cartridge system. The cartridges enable a footwear manufacturer to produce fewer shoe sizes while fitting more of the population. This reduces manufacturing, shipping, warehousing and accounting costs. All levels of the supply chain, as well as the end customers, will greatly benefit from the method of supplying footwear.