Welcome to the site!

I do not plan on paying for the service that she signed up for but also not clearly sure how I can help.

After that, they have to pay rent, utilities, and other costs even if they aren't going to occupy for another month.

You can ask seller to pay closing costs to help reduce costs. 

Issue is he is paying 750$ a month for the 3br/1ba unit, market value for the area for the same type of unit is $1,819.  

When you are a new investor and want to build you will pay 2-3x more than you expected and it will take about 4-6x as long as you think going ground up.

Once you find a house that you believe would be a good rental, meaning desirable to your target market of customers (people within a couple of mile radius of the place), and all of the costs of monthly ownership that you can accurately project fall below the rental amounts that you project that you can get from your target customers, then you have a possible business asset that you can use to produce income, and have renters pay down the mortgage, while hopefully it goes up in value at least with the rest of the economy. 

I would like to see about putting a tiny home on the 2 acre property and selling it to pay off the mortgage on my main property.

I'm giving my 2 cents here as a former Cooperate manufacturing Project manager gone Property Manager:I think the pay structure you have currently is an awesome start! 

Would you rather pay 5% tax or 25% tax?