Jomres 4.2

Jomres' strength is in it's powerful and flexible rate management system. Unlike some rate management engines, Jomres offers a variety of ways to configure rates, allowing you as the property manager to structure the rates to as closely as possible reflect your real world tariffs without custom coding your own solution.

That's not to say that Jomres cannot be edited, it can. The system is PHP based, and apart from two files, the entire system is open so you can edit the source files if you so require. Additionally, the system's various minicomponents (modules, or plugins, if you will) are licensed MIT so if you want to use some of those as a base for making your own plugins and selling them on, you can.

Jomres has four different licenses:

Lite : The MIT/GPL dual licensed version of Jomres, build your Joomla Hotel Booking System for free.
Solo : The license does not expire, but you are limited to having one property on the system. The license is bound to one domain and IP number, so it can be used on only one server. Ideal for the web developer who has a client who wants to offer bookings online to their property (either a cottage/villa, or a hotel, Jomres does not differentiate).
Developer : The license does not expire and you can have as many propertys as you want. The license is bound to one domain and IP number, so it can be used on only one server. Use this version if you want to list many propertys.
Unlimited : The license does not expire and you can have as many propertys as you want. The license is not bound to domain and IP number, so it can be used on as many servers as you need.The encoded files are available as a seperate download in their unencoded format. This is the license you want if you are a web developer with many hotel/property owner clients.