OP, you are asking a great question. 

this is one of those posts where "can it be done," and "should the OP do it," are totally different questions.and I think @Carlos Ptriawan nailed it. 

See, I can tell you "Don't do it", but you have to take my word for it, or I can teach you the logic and reasoning why not to do it, and with the lesson learned here, you can use the new acquired knowledge and insight to actually pick the right strategy without you having to listen to other people that they themself have not got it figured out yet.The BIGGEST mistake I see EVERYONE make here on BP.So OP, again..Why door-knocking?

I still think that's a good place to invest though as it's better than Austin, Round Rock and Tampa where rents are around $1700-2000 with about the same purchase price.I get it, one can find these deals, manage yourself and take time off work to handle issues, renovate yourself and hustle but I think that answers the OPs question.

Hey where is the OP? 

The OP asked about a lien to guarantee payment.

OP you never did define affordable housing.  

After reading stories like the one in the OP, I am glad that I found this community and have continued to educate myself.

Any title company should know this.Since the OP hasn't given much detail, I'm left to the conclusion the lien isn't a mechanic's lien but more of a lawsuit lien where he was served but didn't respond and lost by default, or the title company would have dealt with it.

:/A few nuggets, and others......not so much :)Anyway, Here's my educated response to the OP's question.In general, the Appraiser should be taking into account recent neighborhood market trends (recent sales/comps, absorption, DOM, etc) and current trends (active listings, pendings, cancelleds, expireds, absorption, DOM, etc), and reconciling those trends with the specific Subject transaction.The conclusions may contribute to positive adjustments to the comps, resulting in an appraised value higher than recent comps.Simplified Example: Subject contract price = $102kRecent sales (same models-no adustments necessary)Comp 1 - $95k COE (close of escrow) 6 mthsComp 2 - $97,500k COE 3 mthsComp 3 - $100k COE 1 mthsComp 4 - $99k COE 3 mthsAppraiser determines recent market trends are appx 12%/yr or 1%/mthTime adjusted SP's are:Comp 1 - $102,820Comp 2 - $101,400Comp 3 - $101,000Comp 4 - $101,970The Appraiser may be justified in concluding a market value of $102kThat's one way.