There are obvious and less obvious features. Obvious aspects are the hardware, software, design, promotion and training aspects. But costs can be confusing and can range from 1,000 to 6,000, or more. Hosting requirements involve domain names, web space and systems, but also, assured space availability and technical support. Design needs to be professional yet gauged for maximum effect.
Web marketing needs integration with traditional strategies.
The small enterprise requires particular features of its software, particularly customisation and integration with back office systems. Transactions need low cost low risk, and security.