Facebook Marketplace is likely the best place to look for comps, but ultimately you may need to simply use trial and error to find the right price point (listing the rooms on the higher end and working the price down until you get interest).

As for "buy and hold," there are variations on that, too.  

The truth is, you could read 100 books and still not know enough because certain things need to be learned through trial-and-error.

Trial and error is your best friend.

Maybe they have a free trial?

I’ve used listsource in the past for pulling different lists but I’ve recently downloaded the trial for propstream and I must say I certainly like the user ability much more.

Don't let it discourage your investment career - everything is trial and error - if you've done something you shouldn't have on this one, you'll do it differently next time!  

Might be wiser to frame questions by stating at least a trial hypothesis: "I'm considering buying a duplex in the $400K range in Denver, CO.

They'll have form contracts, recommendations for licensed mortgage loan officers (to qualify your buyers/borrowers) and loan servicers, and be able to explain all the different variations that you might run into.

I've always been a trial-error kind of guy, and some want the expertise going in.