Utilizing Azure's auto-scaling capabilities can significantly affect costs as this feature automatically adjusts the number of virtual machine instances or other service capacities in response to the application's demand. This allows for cost savings during off-peak hours by reducing unnecessary resource allocation while ensuring performance during peak demand. The choice of operating system does not inherently affect costs unless considering the licensing fees associated with certain proprietary OS choices. Storage redundancy options do impact costs, but they are typically a consistent cost, as opposed to a variable one that fluctuates with usage. Number of users has a less direct impact since costs are more closely tied to resource consumption and scaling rather than user count.