So you can eliminate any third party management software.Free software is good, but would you trust that company with all your data, hmmmm let us see, purchase price; account numbers of bank, credit card, loan; bank balances; where you are spending money and how much?

The postcards that are returned are going to be people that the general public doesn't have access to because their data provider obviously did not provide that data.

Some of the appraisal sites don't always have the best data.

He is affiliated with a guy named Thomas Fox out of new New York that represent a company call first data Manhattan.

@Brandon Turner - yes, but a spreadsheet requires thought process which is different from data entry process such as the calculator.  

Once the agents get in, they lock the door to the data and more licenses.

A little bit about myself for anyone interested:I'm looking to be a buy-and-hold investor while continuing my regular job - I am looking to put money to work and would be potentially interested in doing so as part of someone else's deal; I would consider both SFR and MFR deals.I am an investor in my day job (currently private equity / buyouts, soon to become public equities) so may have some bad habits, or at least industry-specific ones, to break; I generally anticipate being relatively analytical / systematic in looking at dealsMy family held a few properties when I was growing up - I have experience personally doing refurbishing work and secondhand experience with property management activities (this will hopefully help me as contextual information, I don't anticipate taking on an active role in refurb or property management in the near future)Right now, I am trying to educate myself on the process of deal sourcing (MLS, wholesaler buyer lists, etc.) and market data sources; in particular, I would really appreciate any input on good sources for publicly available market-level data in manipulable format such as Excel or .csv as well as input from anyone who uses a systematic deal-screening approach both on their criteria and how they get reliable / quality data into a screening-friendly formatThanks for everything people have already contributed. 

Based on those two data points there is no deal.Understandably you are anxious to get in the game, and may have even jumped in without the resources of BP, but you cannot work the property and risk the loss of capital, for the reward of $20/month.  

I have been compiling this type of data for the past few months in the city and the suburbs of Philly.

You can find vacancy data by MSA at https://www.census.gov/housing/hvs/data/rates.html and you can find it by geography at www.factfinder.census.gov.