I'd also vouch for his translation of Beowulf, which is one of the modern great translations of a work. The Translations of Seamus Heaney book also provides some fantastic context for how his translation work and own writings informed each other.
If you want your own copy, Audible has it[2] -- it's about $15 (but they also have a free trial and occasionally Amazon offers a free download from them) -- note that according to some comments, even though it's over 2 hours, it's abridged.
And, of course, there's the printed version[3] -- it's actually bilingual. $12.76 in print, $1.99 on Kindle.
[0] https://www.youtube.com/watch?v=AaB0trCztM0
[1] https://www.youtube.com/watch?v=Zsxxg5P-DnY
[2] https://www.audible.com/pd/Beowulf-Audiobook/B002V5CVPY
[3] https://www.amazon.com/Beowulf-New-Verse-Translation-Bilingu...