Learn more here:
Vendor Independence
You are not tied to a vendor & are protected against poor service, vendor insolvency & price increases.
With open source software you can change your vendors or support the software on your own. You are not dependent on them for minor customization.
Better Quality
Open Source Software tends to be more flexible, reliable and secure.
There are several examples where open source software is better than commercial alternatives:
Linux Operating System
Apache Web Server
Firefox Browser
The open source software development model ensures quality by allowing a large group of people, mainly software users to contribute testing, ideas, bug fixes and software enhancements.
Lower Costs
In general the software itself has no cost, including future upgrades.
Open Source Software applications often run on other open source software. Koha for example uses, Linux, Apache, Mysql and Perl, all of which are open source and free.
The Koha software is free, no matter how many servers, client desktops you run it on, or how many modules you use.
With proprietary platforms like Windows, you may need to pay per server license costs, per client of desktop license costs and for future upgrades of each element in the software stack - operating system, database management system and the library management system. Many vendors also charge more for functionality.