Open SSL is an open-source implementation of the SSL and TLS protocols. The core library, written in the C programming language, implements the basic cryptographic functions and provides various utility functions. Simply stated, Open SSL is the actual SSL program provided by the open source software community. It is the version used by the majority of internet servers. It is also included in every distribution of the Apache Web Server.
No.It is not free SSL certificate. Although, you can create your own certificate in it for free, but it will NOT be accepted for general use, particularly on sites requiring personal information like credit card or banking details. A client would actually be required to tell their machine to accept unverified certificates. For a proper secure site you still have to register the certificate with a recognized certificate agency to obtain an authorization time stamp and approval. You need to keep this updated or machines will refuse to accept connections.
You can use the Open SSL program to create digital certificates to be used with tests.
Open SSL is available from the Open SSL Project at http://www.openssl.org/.