Seller financing opportunity HELP 🏡🆘

[Jake Bourgraf]

So I have an opportunity to buy 3 properties via seller finance.  They are currently rented out and have all been updated and well-maintained. They want 350k for all of them, and the rents are $800, $750, and $500. I think I could increase rents a little as they are all updated and they haven't increased rent. I think I could get $900, $800 and $700 given the market rent. I am trying to figure out if this is a good deal. We haven't talked terms, but they are open to a lot as their main reason to do this is to avoid taxes as they are retired. I also know them personally. Can anyone help me with this? This would be my first real estate investment outside of my primary home and haven't done much on seller finance. THANK YOU