It all depends on what is required such as if design is done from scratch, if online payment is integrated, if an existing web site exists or if a web site just needs updating. If a web site just needs some updates/amends/tweaks, it could potentially before less than £100. A mobile friendly, responsive “brochure” web site would likely be a ball park cost from around £500 and upwards from there. If you want something like e-commerce on the web site, this would be additional costs. Support/maintenance services are available at an additional cost