Giving some rough numbers, let's say the interest rate when they purchased was around 3% and they offer to sell to us for $100,000 cash. 

hello-q: i hope that you have quite the plethora in information about the decide to..build a square space (office like in function) right next to house-to have "reason space" to work from home ('i am forced to work from home bcs of having parent who survives a stroke-cared for on/in house property, bcs putting her instead in assisted living-wouldn't be more affordable/feasable, and many states (california being one) are willing to help loved one(s) to age/stay in place as reason to build these extra spaces in/on property..putting her in the situation as more benefitting i am researching the state orgs to find out what to do=being as stellar the careful/accurate as i can with gathering as to what to do..including the obtain of funding per any grants.and trusting that having your consultation has us getting away from issue/noise over just purchasing/happenstance model in default assisted: residential (multi bed home stead-with all the red tape & fees/tax justify better?

I also own properties in landlord-friendly states where there's no rent control, so I don't need to pay someone to leave in order to increase the rent.To address the other points in your post:This is why having a proper purchase and sale agreement is so important.

Purchase price: $450,000 Cash invested: $450,000 bought a run down mis managed 16 unit property, with my investors, for $450,000 Rehabbing units as they become available and increasing NOI.

Purchase price: $780,000 Cash invested: $300,000 Purchased 6/2020 with 25% vacancy and a gross operating income of $10,800.

Can this still work as a house hack and can still rent it 1 year after purchase?

Purchase price: $550,000 506b syndication What made you interested in investing in this type of deal?

Purchase price: $1,170,000 Cash invested: $900,00016 Unit Value-add property we significantly renovated spending $35k per unit doing interiors, exteriors, and amenities.

Purchase price: $232,000 Cash invested: $65,000 Sale price: $495,000 This was a house that I bought during covid for a project, and I completed all the work on this project myself.

We have been proposed a deal where we would renovate the sellers duplex from a 2 to a 4 and while doing that, our sweat equity would earn our down payment To purchase the property through them.