I recently created my own basemap by exporting a tile package from ArcMap and adding it to my Android device. The problem I ran into was that it wouldn't default to this custom basemap. I then decided to upload it to ArcGIS Online and convert it to a tile layer. I'm now able to set this new tile layer as the default basemap but I'm concerned about consuming a lot of credits. Looking at the credit utilization chart it hasn't consumed any credits yet but I just want to verify that tile layers won't consume credits.