Open Rails is free software and the result of hours of time and talent freely given. Many compatible models of routes (e.g. Mid East Plus), rolling stock and static content such as buildings have been published free of charge.
However, the Open Rails platform can also support commercial offerings in many forms, most obviously models. The Open Rails team has worked with vendors such as Making Tracks both to improve Open Rails and to improve the vendor's models. The more products which are available, both free and commercial, the better for everyone.
Another possibility is for digital tools to support the Open Rails product, such as Markus Gelbmann's free Diesel Power Updater which modifies an MSTS Eng file to suit Open Rails.
Perhaps the most exciting possibility is for add-ons which enhance Open Rails by providing effective solutions in niche areas, such as modeling people or road traffic or moving water. A specialist could deliver and profit from a feature which is popular but considered non-core by the Open Rails team.
These vendors sell or create products suitable for Open Rails:
These vendors sell or distribute products suitable for MSTS:
These MSTS vendors sell or distribute products which have been successfully used with Open Rails:
(New or missing names are welcome.)