Although this isn't the ideal situation, thank goodness for the internet!

You will have to hunt around a bit to determine which ones.

So you should determine an investment strategy and what problems you will fix so you can add value to properties you acquire.This is one common strategy: Acquire a property at a good price and in an area that is appreciating.

My suggestion is to determine which type of investing to do and then research the hell out of it in the forums and blogs. 

I used rentometer to determine rental prices, but they charge after 10 searches. 

If there are comparable use those rents and sale prices to determine the cap and apply it to the present rents in your property.

Size is going to be the biggest determining factor here.

How should we determine ARV on a property that's in a nice area of Macon, GA with no similar comps nearby?

In short, as a Realtor I have access to the MLS which allows me to save time, more accurately determine comps, acquire tax and mortgage information not readily available approximate value to be approximately by these companies and that the information is not always updated in a timely manner.

I have been scouring the internet and testing out some marketing strategies looking for my first deal with no luck so far, but I am committed and determined.