First of all Maria,
You will have to decide on the server-side technology that you are planning to embrace, that is choose whether to run your website on php mysql / asp or asp.net / coldfusion.

Honestly for a new comer like you i would recommend the first option php mysql. Regarding the database. My sql database is the way to go like everyone (or most people) have said.

You can get alot of support online for open source. After all that is the meaning of open source.

cheers