Many self-published authors also are quite capable of narrating their own books. While audiobook narration can be difficult to adjust to, experimenting with tone and speed before trying to record for an audience can help create a good outcome.
However, if you’re paying for studio time, that experimentation can come at a high price.
It is possible, however, to use your own home as your recording studio.
You will need a quiet room with good acoustics, a computer that doesn’t make a lot of noise, a very good microphone, and some recording software.
A good place to look for advice on audio narration is Librivox. In fact, recording a chapter or two, or a few short stories for Librivox can be a good way to learn what works and what doesn’t when you’re narrating. The forums can help you learn how to improve your narration, as well as how to best clean up your audio files with software.
Most narrators on Librivox use the free and open source Audacity software. While it is free, there is a learning curve, so practicing with some public domain stories will help you feel comfortable with the process.