for me it took a week to learn the html basic and used reference to remind me of the things i forgot, xhtml was a week 8 hours a day, x means extended, css still learning. I'm older dude that has had a head injury on a bike so I lost some of the memory. However these are easy compared to vb declarations.
I learned in school the syntax of dos, basic and even today lot of the syntax is similar, and found that education helped me understand the meaning of syntax
To build a professional webpage using the 3 mentioned languages for me css is out of the picture until I can grasp all of it, I can write a basic webpage wiff nifty stuff, still having problems writing a search engine, linking a database with the search, autofeed information into a dialog boxes and a few others.
Been working at it for a year and able to develop a nice looking website with html xhtml and have made sites for a few companies like IN&OUT property maintenance, sunshine surprise, and a few others so yes you can make money. month of studying html/xhtml. If you are smart you would learn very quickly but keep in mind I have some education that did help me with this.