I understand the struggle of finding reliable sources. For 'Beowulf', one of the best places to check is Project Gutenberg, a treasure trove of public domain works. They offer the epic poem in multiple formats, including PDF, completely free and legal. Another great option is the Internet Archive, which often has scanned copies of older editions that preserve the original text beautifully.
If you're looking for a more modern translation with annotations, Open Library might have borrowable digital copies. Just remember, while these sites are fantastic resources, supporting translators and publishers by purchasing their work is always a good practice if you can afford it. The beauty of 'Beowulf' lies in its rich language and cultural significance, so finding a well-translated version enhances the experience immensely.