Build a Website

I need a relatively simple website build using an already existing theme but with validated User registration confirmed by automated email supplying an initial password. with hyperlink to login. Encrypted user login leading to a form with drop down boxes together with certain rules (see the PPT files for what it could look like). User registration details plus form inputs to be written to a database. A script is required to process the form input into a costing which is then displayed on the website & an email constructed of the form elements, User inputs & calculated cost. If the User is a "new client" then the registration confirmation email should include a time-limited discount code. The cost model currently exists in an Excel spreadsheet. The Excel equations will need to be scripted. I'd prefer all of the variables used in the calculation of cost to be included in the database. A secure Admin page will be needed to allow the webmaster access to & modification of the variables used in cost calculation. And the ability to export the data & fieldnames from the database, is required. The remainder of the website is straightforward text and images, although the Home page needs to have a screen-show "video" of Oleum Khaos' digital images. A Contact Us page is required where (non-logged in) Users complete a form which is emailed to the webmaster. I've started building the form using Google Form linked to a Google Sheet, but don't have the scripting skills to build the form properly. Could an Access database be used?