Purchasing Icelandic e-books is quite easy and it is relatively cheap for the value you get out of them as a student.
We highly recommend purchasing an e-book and an audiobook together and to use them together as a reading aid.
Note however that you will almost never encounter written Icelandic on a level below C1. Even childrens' books are written at a C1 level and use difficult vocabulary and phrases. For that reason you may as well want to spend your time reading regular books.
There are over 1,000 e-books and 300 downloadable audiobooks available on the website of the publishing house Forlagið. All e-books can also be purchased through Amazon for the Kindle.
The following is a list of some recommended books where both the e-book and the audiobook are available for download.

Stofuhiti – Bergur Ebbi, 2017 Level B2
Audiobook: 1,000 kr (4 hours)
E-book: 1,000 kr
Stofuhiti is an essay on contemporary life. The writing is witty and the rapid stream-of-consciousness style makes it easy to lose yourself in the thoughts of the author.

Audiobook: 1,700 kr (6 hours)
E-book: 1,000 kr
Mýrin is a typical Nordic noir crime novel. Arnaldur Indriðason is one of the two highly prominent Icelandic authors of crime novels, the other being Yrsa Sigurðardóttir. Both have achieved world-wide fame.

Vetrarfrí – Hildur Knútsdóttir, 2015 Level C1
Audiobook: 2,000 kr (6 hours)
E-book: 1,000 kr
A murder thriller, nominated for the Icelandic Literary Prize.

Draumaþjófurinn – Gunnar Helgason, 2019 Level C1
Audiobook: 3,000 kr (5 hours 20 minutes)
E-book: 3,000 kr
A book aimed at children between 8 and 14. The book is about anthropomorphic rats and their society. The book is quite charming and funny and the voice acting is captivating. Although it is aimed at younger readers, the vocabulary is not that simple.

Fíasól á flandri – Kristín Helga Gunnarsdóttir, 2007 Level B2
Audiobook: 1,500 kr (130 minutes)
E-book: 1,700 kr.
A witty book aimed at children between 5 and 10.

Links
Notes
When purchasing through the website of the Forlagið, items will be marked as:
  • Rafbók = E-book
  • Hljóðbók = Audiobook. Note that you should purchase “Hljóðbók - App” and not “Hljóðbók - CD” or “Hljóðbók - Mp3”, the latter two are only available through a physical copy.
  • Mjúkspjalda = A physical softcover book
  • Kilja = A physical softcover book
  • Innbundin = A physical hardcover book