Think about how many hours of usage you would actually need. An hour a day is enough time to exchange 60MB of information, assuming the connection operates at 25Kbps, according to Infonetics. The flip side of the raw cost consideration is the throughput cost. After all, there is also a cost factor in the time it takes to transfer files or to run an application. Most offices don't need constant, heavy access either back to headquarters or to their branches.
Users transfer some files and log into e-mail.
Small offices can benefit from the increased communication that, until recently, companies with big budgets have been enjoying. For example, a headquarters may allow access to its networks from various branch offices. Another scenario is to let one company access a particular portion of another company's network, say an inventory database or online information service. Many companies have already done so on an informal basis, quite successfully, using standard telephone lines. You want to telecommute.