I charge around $70/hour, I set my clients up on a flat amount per month though. So I take what you have and what you expect, estimate the time it would take in a whole year of work and create my flat rate.
I notice short term rentals are about 1 hour a month of work per property, since we need to track each property's Profit & Loss for Tax time, this is also tracking a mortgage and depreciation as well for that property. LTR are about 40minutes a month each for the same tracking.
Fix and Flips are different, you are running more of a product based business and needs to be tracked a different way, that one is more of 2 hours a month/flip to make sure we are classifying it correctly and tracking it as a project.
Abel is correct that you will pay about $65/month for the software as well, assuming you have more than one property. With just a quick estimation Jon K's bookkeeping is under what I would estimate with only the info he gave me, seeing a bank statement and asking more questions would give me a better idea.
I am more than happy to hop on a call with you and see how I could help and give any opinions.