These can be set as URL Query Parameters
Station = The station ID, defaults to 60003760 (Jita 4-4)
Type = Can be 1 (High sell / Low buy) or 0 (Average), default is 1
Persist = True/false, If you want to save the appraisal for later request, default is false
To get the prices, you need just paste the inventory into the body part of the call.
Retrieves an appraisal added through the site or persisted in the API, :ID should be substituted with the GUID you got from the post