Acumatica comes in three purchasing options: Perpetual, Subscription, and SaaS. Perpetual and Subscription are both for on-premises deployments.
With SaaS and Subscription, there isn't a separate charge for maintenance; it is built into their bundled price. With Perpetual, maintenance runs around 18%. Direct customer support from Acumatica is available for an additional price but they prefer that all support go through their re-seller. They then back up the re-seller as they need it.
Hope that helps.
As always, please keep this within the group. It is not for general consumption or distribution to customers or prospects.