An open house is not only a chance to tour your potential new home, it’s also an opportunity to be nosy without consequence. You can judge others’ decorating schemes and feel out your competition by eavesdropping on other wannabe buyers. Last weekend, New York real-estate writer S. Jhoanna Robledo attended an open house at 400 West 58th Street, and our camera went along. The two-bedroom co-op was listed at $999,000, and several hopefuls checked it out. Meet the Greenwich newlyweds who “want a footprint in the city”; the dog owners who’ve been looking for a year; and the young couple somewhat suspicious of a two-bedroom under the $1 million mark. So did anyone buy? Corcoran broker Jeffery Sholeen tells us that the owners have “accepted a bid” but declined to I.D. the buyer or the price. What would you offer? Watch the video and start calculating.