MySQL is a very popular open source database that offers fast performance, reliability and ease of use. I develop a lot of projects using mySQL and I can attest to the fact that it is a very good database platform for any web project.
The MySQL database is owned, developed and supported by Sun Microsystems, one of the world's largest contributors to open source software.
According to the MySQL website:
"It's used on every continent -- Yes, even Antarctica! -- by individual Web developers as well as many of the world's largest and fastest-growing organizations to save time and money powering their high-volume Web sites, business-critical systems and packaged software -- including industry leaders such as Yahoo!, Alcatel-Lucent, Google, Nokia, YouTube, and Zappos.com."
It's never cheaper and never faster to do this twice (or more!).