I have an opportunity to purchase the MAJORITY of a townhouse complex in Fort Smith, Arkansas but still don't quite understand how to use the analysis calculator to determine if it's a good deal or not.

Here is a decent calculator:  http://www.bankrate.com/finance/mortgages/when-to-refinance-your-mortgage-1.aspx

Does the sale of part of your residence count as regular taxable income, or can it be taxed at a lower rate than my regular income? 

The BP rental calculator has really helped me evaluate deals. 

I want to take a pragmatic and calculative approach and get my education first, but at the same time I'm looking for properties CONSTANTLY.

You need to calculate your "event horizon" meaning how many years you will hold the property.The 50% expense many use comes from over time when an asset is newly built or recently rehabbed with everything replaced that cost will be low.

I haven't had the place inspected yet or anything but here are my calculations, please let me know if it looks good or not worth it.Purchase Price120,000.00Down Payment12,000.00Rehab Cost5,000.00 (estimating this just in case)All In Total17,000.00Rent1,400.00Tax166.00Insurance100.00Management140.00Vacancy 7%98.00Repair 5%70.00Mortgage550.00HOA0.00PMI50.00Water40.00Total Expenses1,214.00Cash Flow186.00Cash on Cash13.13%

As an investor event's like this make me stay away from investing within 5 miles.I have decided to open up my search range within an hour out of the city such as Yonkers, Northern NJ, and even a little further.Also as a primer on calculating ARV to compare two properties use this file http://www.biggerpockets.com/files/user/JasonScott/file/estimating-arv by @J Scott

These are the top deal analyses that I have from the past few days after I started calculating specifics.

The gross operating income (per the owner) was $84,060, @ a 50% expense ratio I calculate a NOI of $42,030.