Costs of development using open source technologies are lesser as compared to proprietary software. Therefore, for the client, the overall development costs may also be lesser as compared to parallel technologies. The scope for platform migration (migrating from one OS/Hardware Setup to another), is more in the case of Open Source software. For the client, this effectively means that porting an application from one platform to another is relatively less expensive. Another great thing about Open Source is that many independent third-party software and utilities that have been developed on Open Source technologies, which cost very little or are absolutely free, can be integrated to existing applications.
Benefits of using Open source software:
* Cost savings typically range from 40% to 50% compared to a product developed from scratch, depending on the complexity of customization
* Development time and cost reduced by over 40%
* Software comes with rights to modify
* Complete flexibility for meeting specific needs (not available with proprietary software)
* Enhanced portability
* Vendor neutrality
* Availability of quick fixes and feature enhancements
To read more and a host of other features click the below link...
http://www.dreamajax.com/Open_Source_Customization.html