There should be plenty of inventory.

Conventional investment loan, 20% down.

Is it acceptable to use personal credit line to fund a down payment on a single family rental on a conventional loan?

Yes you would have to refinance to a conventional loan first, and then use an FHA loan on the new property.

@Nick BrubakerIf you get a conventional/Fannie loan, they now allow you to transfer into a whole lot owned single member LLC with no due on sale issues.

I'm a beginner investor that is pre-qualified for a conventional loan.

The market has become oversaturated with buyers/investors with way too little inventory available. 

I would get a conventional mortgage and put 5% down, You'll still have PMI as a monthly cost but when you reach 20% equity you can usually refi or appraise out of it (ask a loan officer). bottom line is at 22 years old you have the capital to live for free essentially and benefit from home ownership. you certainly have more buying power than $100-$200k as previously stated. $400,000 list price would be $20k down pmt and you could have your closing costs covered using seller concessions.

I did a convention 30 year fixed at 5.35.

Due to better mortgage rates I chose a conventional residential mortgage over commercial.