I've recently re-activated my subscription to Scribd, which in addition to ebooks offers unlimited audiobooks for $8.99/month. I don't recall having heard of this service here.
If you want to try, registering through this link you will get two free months, instead of the usual offer of just one (and I get an additional one free, also; I don't know if this kind of promotion is allowed here. If not, I apologise and please feel free to delete my post):
https://es.scribd.com/g/6mrplf