www.availability.co.nz - $50 for the first room, and $10 per additional room, per month - full availability and pricing and payment solution
http://www.keepmebooked.com - US$30 per month, for 1-5 rooms, with online bookings
http://www.siteminder.com/products/the-booking-button/ US$29 per month up to 10 rooms, also automatically updates AA, Wotif, Roamfree and other channels.