For repair value, a good contracting team will be there to tell you accurate costs, and you can reasonably infer your budget based on purchase price and area market value. 

Those are the kinds of repairs that are tough to budget and could be huge costs.

Based on my numbers I have projected solid cash-on-cash returns (includes vacancy, property management, taxes, repair budget, etc.

I have a friend in the oil service support business that has to fly in guys from out of state during the week and paying them $120k+ as truck drives. 

Negotiate something with your parents who are already in the business ... even if its at $10 an hour, live more cheaply ... have a BUDGET ... and use it- learn from your parents ... you have an unlimited resource already in place learning from you parents ... think about how Robert in the book learns from his rich dad ... get is paid peanuts ... but has an education

Has anyone given letters to new tenants (we have a property manager), with basic budget resources (ala a Dave Ramsey), with the discaimer we are not financial advisors and reviewed by our attorney. 

This includes fixing the foundation work, new flooring and paint throughout, and if allowable in the budget I would include updating the bathrooms and kitchen(not necessary as a rental for a family). 

So your purchase plus rehab budget would need to be less than about 65% of ARV, as determined by the lender's appraiser. 

One of the best ways for you to come up with a rehab budget is go into the house and make a list of all the items you want to have fixed.

Best advice is to put together a budget with a goal toward affording your first acquisition.