If it's a senior lien foreclosing and you can see the recorded foreclosure action it typically states what was owed at the time of recording and then you can see what it sold for at auction which is a solid way to estimate.

I've already purchased a lot of chairs, side tables, writing tables, and 12 mirrors from the historic Waldorf Hotel Auctions in MA.  

I have never attended an auction before but I would like to, seems very possible to find a good deal.

If a judicial foreclosure. the Final Judgment filing (30-45 days before the auction) will have an exact amount. 

About 15 years ago there was an automotive auction constructed across the street from the property which increased the value significantly.

Perhaps you could wait for some auctions/foreclosures that may be increasing in the next several months..Forrest Faulconer

The previous owner got it from auction with the intent of house hacking it, he owned it for five years and never got past the lower livingroom.

What’s the best way to tap into that equity to buy at auction.

On an out of state property that I was looking to pick up at auction, I was able to confirm that the photos on the listing were old, & the house was in much better condition than the listing appeared. 

@Nabil Suleiman Are there certain sites you recommend for foreclosures or is it better to attend auctions?