865 Montgomery can be bought for $2M, $2.25M or $3.5M, your choice.

https://www.trulia.com/property/3004743570-865-Montgomery-St-Brooklyn-NY-11213, or hey here's a different price http://www.loopnet.com/Listing/20194596/865-Montgomery-St-Brooklyn-NY/

Clearly, Loopnet should start advertising that one can get the exact same property for $1.25M less than on Trulia.

Backstory: This house is posted on Trulia, Loopnet and Zillow for 3 different prices. But apparently this house has a lien on the property which makes it hard to sell.

Doesn't make it hard to sell at all. Lien gets paid off at the closing. As long as the lien is for less than the sales price it's no problem. Many houses have liens. They're called "mortgages." It's the same principle.

Would a city lien make it harder?

Only $2M on Redfin. Clearly it pays to comparison shop. https://www.redfin.com/NY/Unknown/865-Montgomery-St-11213/home/40715126