@Joe Meares depending on the quality of the area, you might investigate payrange.

($200k) I don't care where the land is or how undeveloped.What are some good resources to begin investigating if I want to obtain large plots of land, possibly unconventionally, for the cheapest possible on a per-acre basis?

That being said, as @Marcus Auerbach stated above, the spread will be rather thin under the 100k mark so I suggest investigating other neighborhoods that offer more variation in home values. 

I will have to investigate the seller finance option @John K. suggested. 

They can get re-syndicated for another 15yr stream of LIHTC (10 yr credits, 15 yr compliance) Just realize:1) It'll be 4% tax credits2) Usually you need a "chain of title" - Same owner for the past 10 years.3) At 15 years, you may want to investigate a QC (qual contract) where you offer to sell it to another operator and if you get no bites, you can get out of the LURA - Different for each property. 

Investigate how appraisers in your area value houses and use that to your advantage... sq ft, bd / ba count, materials used in kitchen or bath, etc ...

IF they do, then you investigate further.

Do the investigation...get a quote...factor it into your offer.Do not sit around and wait for the "perfect" opportunity to come along.  

@Craig SmithReciprocity does exist between states, but you would have to investigate the state laws of which you are moving to.  

Inspect on a regular basis2. have at lease 3-5% money on the line, non refundable, DO NOT FINANCE IT.3. investigate your tenant buyers history 3-4 landlords, not just last one4. see how they are living now, surprise them when visiting, before they move into your place.