Newbie Investor with 3 property offer

Hello my BP family. Need your help and honest feedback. I have been investing in real estate on the side for the past few years but am extremely eager to make it my career. I currently have a single family and duplex that I use as rental properties and have a very good amount of equity in each of them. I was presented with an interesting offer from an older gentlemen that is looking at getting rid of his 3 rental properties, all three are duplexes. He said he would sell me all or just 1 on a land contract with a 5 year balloon. We have not discussed pricing but I would like to see what you all thought a good price point would be.  I have included all the information that I have below along with screen shots of the Analysis tool. Your feedback and opinions are greatly appreciated.

Property 1-Upper Unit 2BR $575/ month Lower Unit 2BR $500/month. Exp-Water and sewer around $110 a month, taxes $2457, Insurance $576. Tax Base Market Value=$96,400

Property 2-Upper Unit 3BR-$550/month Lower Unit 3BR-$575/month. Exp Insurance $582 Taxes $2837 Tax base market value $113,000

Property 3- Upper 1BR-$390/month Lower 1BR-$420/month. Exp Insurance $446 Taxes $1727 Tax base market value:$67,000