As of December 2015, all SPIRIT data will are available for free here :
Do not hesitate to send us some feedbacks about the database. Keep us inform about your results using SPIRIT DEMs and images.
For EU researchers, new DEM production can be obtained through the ISIS (www.isis-cnes.fr) program at the cost of ~700 euros / 15000 km². Do not hesitate to contact Steven Hosford if you want to check your eligibility to the ISIS program. You can also contact me to get a copy of a tutorial (written with Sverrir Gudmundsson from the University of Iceland) explaining how to order SPIRIT data through ISIS.