VDI allows organizations to virtualize desktops by running them as virtual machines on centralized servers rather than individual physical machines. The document discusses implementing a VDI solution for the City of Hallandale Beach. It estimates that deploying an initial 50 VDIs would cost around $90,000, with additional costs to scale up to 350 VDIs. While VDI provides benefits like easier management and mobility, the costs include new storage, software licenses, thin clients, and implementation fees. ROI is not expected until year 5 due to upfront infrastructure investment.