On AWS, the BYOL order type is available.
BYOL offers perpetual (normal series and v-series) licensing, which is an hourly subscription available with marketplace-listed products. BYOL licenses are available for purchase from resellers or your distributors, and prices are listed in the publicly available price list which is updated quarterly. BYOL licensing provides the same ordering practice across all private and public clouds, no matter what the platform is. You must activate a license for the first time you access the instance from the GUI or CLI before you can start using various features.
For BYOL, cloud vendors charge separately for resource consumption on computing instances, storage, and so on, without use of software running on top of it (in this case the FortiGate-VM).
For BYOL, you typically order a combination of products and services including support entitlement. See Support Information on the marketplace product page.