Cap Rate Data Source

[Nick Horob]

I'm looking to get into multi-family investing.  I would like to become very familiar with 2-3 markets/sub-markets in addition to my home market (Fargo, ND).  

I would like to research macro rental data and trends for markets across the US.  Is there a data source where I can find at what cap rates multi-families are trading in all the MSAs across the country?

I know there is no free lunch, but I'd like to try to compare cap rates to employment growth (or lack of) to try find markets that offer attractive risk-adjusted returns.