In order to make it easier to add price providers: let them do the work:
add an option to add a download url of price providers, to download a (defined) xml file(s) with card prices (as defined in previous feature 318).
This way, when someone wants to support MagicAssistant, all they have to do, is to offer xml files on a certain location. No special parser or treatment will be needed in that case.
On startup, MagicAssistant can check if the xml file at the Price Provider side has been changed, and ask to update the file if so.