I used to be one of those who thought these book were pure gimmick. "Who actually reads those?" I'd ask myself, passing them by for something that looked more promising, but cost more. Let me tell you, those books are written for the average person, and they have great stuff. My hubby is reading one now about a particular computer program.
My point, however, is not those particular books, but the simple fact many of us can't afford to go out and buy writing books, so we are stuck with looking around on the web or borrowing from friends. While borrowing from friends is nice, they usually want the book back and you can't mark up the margins.
With this in mind, I thought it might be helpful to point out some of the sites on the internet that help with writing. There are lots of organizations that are free and give you access to critiques, grammar help, etc. Along with those organizations, there are also many sites out there with generic help (such as spelling, punctuation, etc.). Some of those places are invaluable.
If you've spent any time on the internet as a writer, then these sites will possibly be ones you've already visited. If you're new at the whole thing, then perhaps they will be of benefit.
CostumeGallery.com -- This is a great place if you write historical fiction or non-fiction and need to know how people dressed.
Dictionary.Reference.com -- This site is great if you don't have a dictionary, thesaurus or need other basic grammar helps.
Writefromhome.com -- This is a good resource site for those who want to make a living writing from home.
writemarket.com -- This site has lots of resources for all kinds of writers. It takes a little delving, but it's good.
wordtrip.com -- this is a membership site for writers. They have challenges, contests, suggestions, etc. They're great.
writersdigest.com -- writers digest is a great magazine, and the site has lots to offer the writing enthusiast.
writing.com -- is another membership site. Membership is free, but there are ugrades that give you more options, such as add free membership, etc. I've been a member for several years, and they are great for critiques.
latterdayauthors.com -- there is a forum on this site where the LDS writer can find a home. They're great, and there are many published authors to lend their support and wisdom as well.
advancedfictionwriting.com -- this is kind of different, I didn't find it worked for me, but several people swear by it. You might find it worth your time.
.lifeformz.com -- this site is great if you're feeling in a slump and can't come up with anything to write. They are a tag line generator, and promote madwrites.
junketstudies.com -- this place is great if you're looking for help with writing skills as well as do's and don'ts.
writers.net -- this is a great resource site as well.
These are all sites that I've bookmarked on my computer at one time or another and I've used each one. There are many more out there, all you need to do is search. Don't let lack of knowledge stop your writing or hinder your efforts. If you don't find what you're looking for or need on the internet, libraries are a great source as well. Just keep writing!