Pricing for a chassis is about the same as the cost of an equivalent number of separate servers. In fact, the blade system might be more expensive, but the lower management costs of the blades over its lifetime will probably more than make up the difference, as long as the system is fully utilized. You can buy some systems with less than a full complement of blades and purchase more blades as you need them; if this appeals to you, however, check how long the existing blades have been in production, and whether earlier blades can work in the same chassis. You don't want to buy a system and have the blades be out of production by the time you need more.
One big trend is to use virtualization to consolidate many operating systems into a single large hardware setup. If this is something you're considering, a blade system may not be the best choice for you. Although it is possible to use blade servers and virtualization in conjunction, systems that run several to dozens of OSs on each of many blades are probably beyond the needs of most small businesses.
If you're keeping a number of separate hardware servers--either because you don't want to deploy virtualization or because you're running applications that fully utilize the hardware they're running on--then blade servers can reduce the cost of managing the systems.
Blade servers have some limitations compared with separate servers, though. The first is expandability: While even 1U servers may have two or three PCI-X or PCI-E slots, blades may not have any. Separate servers also typically support at least four drives, providing more storage capacity and performance than you can get from the one or two 2.5-inch drives typical for blades. (Some blade systems, though, offer high-performance Fiber Channel connections or 10 Gigabit Ethernet connections to each blade, or shared high-performance storage.) If you need specialized hardware, blade systems may not be an option.
Whether blade systems are a fit for a business has less to do with the kind or size of the business itself than with the organization's IT demands. If your business tends to buy one or two servers a year, justifying a blade system is difficult. If you typically purchase clusters of 4 to 12 servers, the savings in management costs and potential power consumption may make buying blades worthwhile. Since the blade system could cost more initially, an organization with a single administrator might not save enough in management costs to make up the difference.
Differences Among Blade Servers