Which language you are using for building your website? I am using PHP as it's easy for coding and uses mysql as database. Also, many free hosts are linux based and provide mysql database.
PHP, because it’s open source and works well with all the browsers, unlike ASP which some times doesn’t work with Opera and Firefox. Of course there are tons of free php scripts available which are easy to use and configure.
Before I went into business for myself, I did a lot of ASP sites, but for my own clients now I use PHP. It's cheaper for them and there's no worry about all the expensive licensing for the Windows stuff that ASP needs.