What about calling for rent properties and asking if the owner is willing to consider an offer to sell?

While this can be a good strategy, I don't think you need to even consider an LLC or series LLC until you have multiple (4+ properties).

Depending on the equity that you have in the property, you may consider an LLC as an asset protection tool.

If you want to build a portfolio....consider an FHA Loan FIRST.

@Tyler Lee You might consider an FHA 203K.  96.5% LTV. 

Keep things simple, do not create any payroll for him and focus on making more money.Now, if he makes $75k net, which is after expenses - then he needs to consider an S-corporation and W2 payroll for himself.Bookkeeping is simple, really: record everything he spends for business in any form that is simple for him: old-fashioned notepad, Excel or Google Sheets if he knows how to use them or apps like Expensify or TaxBot.

We will consider an LLC as we scale.

I know I do not consider an RE investment unless I project over 20% Short-term return on investment and typically achieve far greater (about half my RE purchases are on the infinite ROI). 

@Davey DavanoskiYou don't really pay yourself.Flips are different, the profits go towards your income.Rental properties generate passive income, but if you're looking to retire from a day job it's not usually possible for the average person owning 1 or 2 properties.As an example let's say you have a target goal of $300 positive cash flow to consider an investment.

If I can put a place on the market, rent it quickly at market rents, then I don't consider an option like this.