How much do e-books cost?
Apple has two applications named "iBooks", both are free, but you have some system requirements:iBooks for iOS version 3.2 needs iOS 7, so this app only runs on newer i-devices (iPad 2, iPhone 4, iPod touch 5g, and newer); if you try to download iBooks on older devices, you will get prompted to load the newest compatible version instead (or cancel), so e.g. on an iPhone 4 still runing iOS 4.3.5, you get iBooks version 2.2 (931).iBooks for Mac was introduced with and needs the system version called Mavericks (that is Mac OS X 10.9) - in fact, you cannot even load it seperately; so that rules out every Mac that Apple chose to, e.g. the Mac mini 2,1 from around 2007.While you might be able to jailbreak and/or hack some (not too much) older devices to run iOS 7 / Mavericks, this is limited to people with "hacker spirit". So if your device fits into the category mentioned above, iBooks costs nothing extra, apart from download fee maybe.