If you ask Amdram to design the pages there will be a small charge. This charge will be agreed in advance and covers everything - no hidden extras. You're probably looking at somewhere between 10 and 15. With no further charges for updating. This fee does not fully cover somebody's time for preparing the pages, but is a token payment towards it.
Web pages can take several hours to design.
Develop 4 pages with page 1 being the entrance - the page that every visitor sees. This page could contain information about your group, details such as where they rehearse, where they perform, when the next production will be, when the next auditions will be, contact details, etc. It would also contain links to the other three pages. Page 2 could contain information about the current production. A synopsis of the plot, performance dates etc, could be shown here.