Making an offer below asking price

I have been a renter in NYC for the past ten years, and have decided it's (past) time to buy. I have found a fixer-upper co-op that I am interested in making an offer on, but am somewhat clueless as to how much to offer. I found an article* says: "According to MSN Real Estate, offering any less than 85 percent of the asking price may be risky. Bankrate reports that an offer that's 5 to 10 percent... [more]

I have been a renter in NYC for the past ten years, and have decided it's (past) time to buy. I have found a fixer-upper co-op that I am interested in making an offer on, but am somewhat clueless as to how much to offer. I found an article* says: "According to MSN Real Estate, offering any less than 85 percent of the asking price may be risky. Bankrate reports that an offer that's 5 to 10 percent less is reasonable, but in some markets, even 5 percent may be too much." I know there is no magic percentage that fits all situations, but is there any consensus about the general practice in the NYC co-op market at the present? Also, how do you determine whether an apartment that is vacant and unrenovated is priced fairly, when all similar apartments that have sold recently are renovated? *http://www.homefinder.com/content/Buying-Guide:Understanding_the_Offer_Process [less]