This can be a very big area to implement depending on the type of requirement. For instance, a web based customer facing portal for information can be done in a number of CMS systems, some of which I can implement.
However a bespoke system made to a requirement with accessible endpoints for business to business client interaction, would take longer and would require increased technology resources depending on the overall load the system would have to handle which therefore would cost more.
For every type of business whether it be small or large than I have a solution