Audiobooks are a growing market, but it's best not to be tempted to pay a lot to get one. A friend, a far more successful bestseller than me with her ebooks, spent $2000 to get an audiobook made of her most popular book. Even after three years and a lot of promo effort, it hasn't earned out. I did three audiobooks on a far lower budget, but again, the earnings just don't justify the time invested, even when they can be produced for no cost but my time.
There are ways to get audiobooks without a big spend. Many authors are learning how to narrate and produce their own, which can then be uploaded to bookselling sites using ACX (a division of Amazon) or Draft2Digital. Many authors are getting into selling directly via their own website or sites like Gumtree or Etsy. I haven't tried this - where we live is way too noisy to record, we don't have the space to soundproof a closet to make it an audio booth, and I don't think it's worth me investing time in the learning curve to get competent with audio editing software. But there plenty of info out there about authors who've gone this route.
Other options - ACX have various audiobook production options from full pay-per-finished-hour to getting a human narrator to produce your ebook for no upfront cost, taking instead a 50% royalty share for 7 years. The catch is that good narrators won't usually do all that work unless they can be sure sales will be good. I got in early on this when there were still good narrators doing royalty share, or you might luck out and find someone new, working to build a portfolio and willing to do royalty share. But my lovely narrator sadly earned very little for my audiobooks, I felt so bad I paid her a big bonus payment I really couldn't afford because she'd poured many hours of work into them and was lucky to make $10 a month from them! The royalty share contract also requires that the audiobook be exclusive to ACX for seven years, which means it can only be sold through them on Amazon or iTunes, and the audio can't be used anywhere else. After the seven years, you own the audiobook and can sell it anywhere.
Using ACX to contract narrators to produce your book using pay-per-finished-hour can cost anything from $50 to many hundreds per finished hour, but you own the finished audio and can choose to sell it wherever you want. Findaway Voices is another quality non-scammy audiobook production business offering pay-per-finished hour. But as my friend experienced, it's not likely for anyone apart from the big bestselling authors who can spend $$$ on promotion to make their money back when paying a good narrator to produce their audiobooks. I don't recommend it unless the author really really REALLY wants an audiobook and is happy to lose money to have it. But it may be possible to get a pay-per-finished-hour contract with a good but new narrator for a reasonable cost via ACX.
Google Play Books offers free AI narration for audiobooks that are listed for sale with Google Play. There are also AI narration apps of varying quality. Not everyone is okay with the idea of AI narration, but it's an option.
If you can and you would enjoy the process, DIY is possibly the best option!