Current rental sell or keep?

[Zach Gring]

I have a rental it is 4/2 was my primary 3.5 years ago. Have had the same tenant the whole time I raised the rent up to 1850 after the first two years. My tenant really wants to buy it. I thought I was doing good with about a 340$ surplus monthly after expenses, however recently I ran those numbers taking into account 130$/month for vacancies and then 10% (185$) for repairs and now it’s only cash flowing 30.00$. Here is where my question lies I have no rental comps in the area or surrounding towns that are of the similar amenities to base a higher rent off of. Lease is up in October she said they’ll be ready to buy in early 2021 or late 2020. Do I sell it not knowing if I could still rent it for more after they move out based on no serious comps.

Thank you in advance