As Roymondo says check the local library I’m Northants based and they do a free app for your phone where all the audio books are free the downside is sometimes you have to wait days for the title to be returned from the previous user, I also rent the audio cds from the library if i’m waiting for a book to be available, they are a couple of quid and if their is a certain audio book you want you can request cds to be ordered in.