Computer-types, who are also frugal, may wish to learn about Goalkicker. That is, if those peeps don't already know about it.
The company is similar to Packt.com. There are two major differences, well, maybe three. Goalkicker doesn't publish nearly as many titles (I counted 36 of 'em). Goalkicker's titles tend to be on less-technical, and more-common, subjects (even I, who am a virtual illiterate about computer stuff, recognized many of the books' subjects). Third, as far as I can tell, _all_ of their books are _free_.
You can get the books in any format that you please, as long as it's pdf.
www.goalkicker.com.