My first cost-saving principle is to do more with the storage you already have. The average rate of productive utilization of storage is well below 50%, even without considering "overhead" factors like RAID levels, mirrors and replicated copies. In fact, in a study I conducted in 2003, I found that drive utilization on Windows systems was under 30% across more than 3,000 production data center servers at more than two dozen companies....
Since then, I have continued monitoring the ratio of used space to free space on systems of all operating systems, and the situation has not improved much.
So what can you do? Move to a more-flexible storage system. iSCSI is a favorite, especially where cost savings are concerned, allowing a large number of servers to efficiently share a smaller pool of disk. iSCSI storage currently costs just under twice as much as server-grade internal disks, but you might only need to buy a third as much. Although booting from iSCSI is now a viable option, it's not yet a proven solution. But combine high-utilization iSCSI and server consolidation, and you might save as much as a third of your server and storage budget next year.
This illustrates another cheap storage tactic: Spend a dime to save a dollar. Many organizations are trying to make do with older storage hardware, even skimping on maintenance contracts. This presents a huge risk to the business, and the supposed cost savings might be an illusion. Per-gigabyte storage costs are halved about every 18 months, but maintenance contracts are priced based on initial purchase price. In many cases, the entire storage infrastructure could be replaced with newer, cheaper, and technically superior devices for less than the cost of maintenance on the old devices. Surely, design, implementation and migration costs can add up, but the cost and risk reductions might make a hardware swap worth the investment.
Another cheap storage tactic worth considering is a switch from Windows-based file servers to special-purpose NAS appliances. I recently worked with a bank that was able to consolidate file services from 30 Novell NetWare servers to a single Network Appliance filer. Again, service levels went up and management costs dropped dramatically. Snapshot-based file restores and replication were icing on the cake. Consolidation and standardization on high-quality hardware are always worth the effort.
Finally, don't overlook your personnel. Spending a few thousand dollars on a training course is well worth the investment. You will be rewarded with better storage management and less employee turnover. Make a commitment to send everyone in IT to at least one technical training session per year, and consider business courses as well. As IT is professionalized, employees who understand finance and operations as well as technology will become storage stars.