The property taxes are given on the listing sheet you're looking at; just scroll down further to find them.
As far as why a house would drop in price over a year, there are many possible reasons: it was overpriced to begin with, or the owners are desperate to get out, or the owners have already moved and just want to get rid of the house, or previously unrecognized problems with the property could have been found, or it could just be market changes.
If you're serious, your best bet is to talk to a buyers broker - a Realtor who is working for YOU, not for the seller. Ask your friends to recommend someone, and then interview a couple of Realtors to find one who you're comfortable with.
Linda Snyder, Marketing & Development
On the Spot Rentals
Box 282, Auburn ME 04212
C: 207 740 2241