In this type of situation, they want low interest rate with low down payment also.

And many of my clients are taking on the BRRRR method. 

Find Brandon's videos on YouTube for the "four square" method of analyzing homes and practice.

The key will be to set up terms so your monthly payment works.

However if you have enough reserves, 6mo or greater then I'd say chance it but a couple of missed payments from the tenants and you have to foot the payments out of your own pocket.I'm all for taking risks but I think you really need to evaluate the age of the major systems so you don't get hit with a bunch of cap ex all at once as well as your reserves. 

Your son is responsible for making payments on time or ruining this seller's credit. 

So it could take a decade to get to todays market rent. 2) it’s almost impossible if not impossible to non-renew a tenant, especially if you’re not an owner occupant. 3) As a seller, even if I could remove paying tenants I never would without a non-refundable payment from a potential buyer that covers all vacancies for 6 months if they fail to complete the purchase. 4) You MIGHT say as a buyer that’s worth it.

What kind of account or vehicle would you suggest to start saving down payment money for my first rental property?

.- get into real estate with a lower rate and lesser percentage down payment.

If you have extra cash at the end of the month, then do double up payments on the mortgages so the principle is reduced and this will increase your heloc room.