The ninth edition of Liddell & Scott's Greek-English Lexicon (LSJ) has been freely available in electronic form since 2007, having been released by the Perseus Project under the Creative Commons Attribution–Noncommercial–Share Alike 3.0 license. In addition Lighthouse Digital Publishing has added all known Greek word-forms and parsings to the lexicon. This allows direct look-up of any poly-tonic Greek word-form within a given text. Search can also be performed within the lexicon by typing the headword using the Kindle keyboard and Beta-Code transliteration. The LSJ is a must have for any serious student of Greek and the Kindle edition works wonderfully fast. The small fee is to support continued development of the Kindle version and meet the minimum Amazon price.
Notes:
1: The lexicon works only on E Ink devices i.e. the First generation Kindle, Kindle 2, Kindle 2 international version, Kindle DX, Kindle DX international version, Kindle DX Graphite, Kindle Keyboard, Kindle 4, Kindle Touch, Kindle 5, Kindle Paperwhite 1st and 2nd generation.