While Fhotoroom is a free app for both Windows Phone and Windows 8, add-on packs are available for in-app purchase with the Windows 8 version that added editing filters and brushes as well as removing the ads in the gallery. The charge was minimal and helped cover the server costs.
However, in the spirit of the Holidays, for the next two weeks these add-on packs will be free for the Windows 8 and RT versions of Fhotoroom. Those already enjoying Fhotoroom on their Windows 8 or RT device, but haven't purchased the add-on packs, should see the unlocked features automatically (or at least that was the case with my copy of Fhotoroom).
You can find Fhotoroom for Windows 8/RT here in the Windows Store. The Windows Phone version is available for both Windows Phone 8 and 7.x devices, is a free app as well and you can find it here in the Windows Phone Store or by scanning the QR Code below.