We got a bunch that was discounted online to $0.61/sqft delivered Freight to a property. 

From what you describe, assuming that existing rental income is honestly reported on your tax returns, you should be able to count both rental income from the existing property, and projected rental income from the other units in what you are buying, assuming a local REI-friendly lender with minimal/no overlays (those are the reason why you see conflicting stuff online). 

You can also check their reviews online at Google, Facebook, or Yelp.

However if this is purely investment (is no plans to move in after some time), you need to objectively do the math on your expected return given what you think price appreciation will be over the life of your ownership ( @Leo Kotschenreuther makes an excellent point) , weighting the risk of a downturn and your ability to continue to fund this investment, and compare that to using your 500k +2k/month to fund any other investment (Amazon stock, bonds, passive investment in a syndicated deal elsewhere.... ) We are holding our San Jose MF, but I've stopped looking for my next deal in silicon valley... property here is all priced for perfection (ultra low cap rates, neg cash flow, smells like 06-07!)

These days, you can check Zillow and find out how long it's been on the market, so if it's on the market for over 90 days, they're asking too much.As to real estate taxes, figures are available on online, and can go up on changeover of ownership.

@Kelvin Tian here is a calculator that has an amortization schedule and what happens when extra payment goes to principle. www.free-online-calculator-use.com/extra-payment-mortgage-calculator.html

Hey guys, I was wondering if any of the professional property managers could share with me what online tool do you use to collect payments online from tenants?

Go to the county clerk of courts online docket and select foreclosure search. 

Sometimes you can find it for free online on a county or cities website.

But again, you can lose money, unlike a money market or online savings account.