What the owner bought it for is irrelevant to what it's worth in this market so, maureen, be careful when doing that calculation :) Take into consideration market conditions - local sold data - as well as the house and size of the lot.
JC, I want to correct a calculation I did below ... Your 280,000 offer on a 339,000 price is a 20%discount not 8% (big difference, sorry). I actually found the property you are interested in ... Looks pretty decent (using only pictures and listing data) and luckily is not a short sale. According to the assessors data it was bought in 1992 for $128,000 and is currently vacant. The original price was 359,000 so your offer is actually around a 30% discount and the Malden average is 9% (see below statistics) so your offer is very low and may not get a response. That said, I would be shocked if they didn't negotiate considering Malden is experiencing a pretty tough market right now:
I did a quick search of sold properties in the area with similar square footage, full baths, bedrooms, half baths, and lot size, and in the last 6 months the cheapest one to sell was for $309,000 (it was a drastic price drop, started at $387,555).
Based on all this info it seems like $280,000 might be a stretch but you could always low ball and see where they stand. The other option is to be patient ... see if the property stays on the market and experiences another drop. From what i can see the sellers aren't financially into the property too much so they may be willing to go with a lower offer just to move the property. You never know.
Make sure you hire a buyers agent when you get ready to make an offer :)