The Backdoor Broadcasting Company is a webcasting service, and will therefore charge the organisers, not the listeners. Most fees are negotiable, depending on the size of event and levels of technical complexity. But to get an idea about the cost involved, the figure of £72 per recorded/broadcast hour (minimum 90 minutes) can be taken as the average charge. This includes the recording and/or broadcasting the event, a permanent webpage with players and downloads, as well as a physical copy of the recording in any format.
Organisers can, if they wish, have gating mechanisms attached to their broadcast, either for security reasons or for charging the listeners. Setting this up requires a separate domain and organisers will be billed accordingly. Other charges are likely to be travel, lodging (if overnight stays are necessary), editing, transfer to other formats, additional webspace/design, and advertising. All prices are exclusive of VAT.