Each year, Microsoft’s Eric Ligman posts to his blog a large collection of free ebooks from the software giant. This year, he’s posted the largest collection ever: 130 free Microsoft eBooks including resource guides, step-by-step how-tos, etc. The vast majority are geared towards IT types who manage various Microsoft enterprise software platforms. However, the collection also includes helpful quick start guides for popular Microsoft productivity software like PowerPoint and Excel, along with books related to Microsoft Office 365.
You certainly can’t beat the price.