THE INFO WAR
Finding information online that isnt compromised or full of trojan horses is no easy task. While you can obviously torrent a lot of manuals or information, its much quicker to just load a web page and look it up. Here are a few websites I use for working on vehicles that have been helpful:
This website is not a repair website, but rather a list of cars and their reliability from a database of research done on particular models. It is very useful when trying to decide what car to buy or tell someone which car is more reliable. Often people will ask me what to buy since I work on them all the time. (Don't tell anyone but my answer is usually Toyota)
This website has been very helpful when it comes to diagnosis and I don't have the info on hand. Doesn't matter who you are, there is nothing like a good diagnosis to save time and money. It includes particular models and cars but is most useful for American made vehicles.
Here is a place you can go to find out local prices for repairs. I have found it useful for charging a fair price if I'm not charging an hourly rate. I also refer customers to this website when they have questions about what a repair will charge or where to go for a repair.
If you own a mazda miata or are working on one this is a great resource for miatas. I used it in my miata rebuild and I'm sure others have too.