When I looked into these devices in May, the ABS material was $25 per cubic inch. Most of the professional machines are designed to be run 24/7. I.e. if they stop running for too long they get clogged with goo and have to be serviced by a technician.
If you're in the Bay Area, TechShop in Menlo Park has professional versions of these machines and often hosts seminars where you can learn a lot about them for free, or for a moderate price ($30).
If you're in the Bay Area, TechShop in Menlo Park has professional versions of these machines and often hosts seminars where you can learn a lot about them for free, or for a moderate price ($30).