I am a CPA and moved from public accounting in tax to industry about three years ago. I have continued to prepare tax returns as a side hustle.
I charge $125 an hour plus processing fee. When I bought my tax software, I chose "pay-as-you-go" option, so for every return I pay a filing fee before I can submit it. I pass that 100% on to my clients. Software is very expensive and the program I use now is not nearly as sophisticated as what I was using in my firm. This has led to some issues. For more complex return, I have to override my software at times and that makes me nervous from a liability standpoint. I do not currently carry E&O insurance, and have turned down work that I am capable of doing but would give me too much exposure. I'm trying to actually pare down my list to only friends and family.
I have made about $10k net per year the last three years without really trying. I just carried my clients over so I don't have to do any business development, I get more referrals than I want.
I am scaling back because of the liability issues I mentioned above and because I don't like being on-call for clients outside of working hours. I also had never worked from home before so not having all the office functionality was frustrating.
However, every CPA I know in town has too much work. There is definitely a market for the service and you can make a nice income.
Let me know if you have specific questions.