Websites with alot of text, like wikipedia, very easy.
Websites with constantly flashing /refreshing gimmicks= extremely annoying.
Website with alot of graphics and graphic buttons= nearly impossible.

To break it down further:
Book research, online banking, emails, reading stories/books= quite easy.

Finding movies, watching youtube, shopping, looking for downloads= slightly harder but still within reason.
Facebook, reddit, other online social medias= can be very frustrating but with a bit of patient and maybe a smashed computer or two, can be done.



Google map, image search, capcha entries= forget it, it's not going to happen soon.

We use special software to either zoom the screen way in and/or read stuff out loud (look up Zoomtext, JAWS, NVDA for examples).

Lots of websites don't (completely) work with these software because the software uses the HTML tree of the site to read things in the right order. And a lot of web devs just simply don't put in the right HTML code the software needs to navigate totally correctly.

It would be allot easyier if it were like the old internet. Here is a good explanation http://www.hobo-web.co.uk/design-website-for-blind/. There is too much going on and screen readers have a tough time navigating it. My SO uses a program called JAWS to navigate the internet, email, word and other programs but allot of times JAWS fights with everything and it can get very frustrating.

Very easy these days. There are several programs that can allow a blind person to use the internet. Many blind people use the popular JAWS. I use NVDA, a free version that does more than JAWS. In my opinion, better than JAWS.