I'm still an amateur in the field of web design. I feel that my web designing skill is not that good enough and I would like to learn more to become a professional web designer. Do you know any legal websites that offers free tutorial of web design? I don't want to take classes because I'm tight on budget.

http://www.tutorialized.com/
http://www.good-tutorials.com/
http://www.envato.com/

this should get you going, envato runs several websites, marketplaces and tutorial sites!

What do you need tutorials for specifically?
You could do a basic Google search and find plenty of tutorials on the specifics you are looking for.

You could also search youtube for video tutorials if you are not the reading type. There is lots of helpful information there.

I second the youtube suggestion. I found a number of useful things there when I was first starting. There are tons of varieties and perspectives there, so it gives you a nice mix of stuff.

You need to learn

HTML
CSS
Javascript
PHP
AJAX

w3schools.com is a very good web page that can get you started.

theirs a lot of tutorial on google, i would start with HTML aand go on from their.

you should get dreamweaver program its one of the best editer..

Being tight on a budget and getting DreamWeaver doesn't fit on the same sentence. However, there is certainly a ton of free info all over the Internet. Good luck with your web design career.