Of course, the seller can "ask" for any price they want. Will they get a buyer? Not likely if it's overpriced. There can be several valid reasons for the price increase. Perhaps the $307,000 was a "bargain" price, and now the new owner is selling at true market value. Perhaps they made significant improvements. Perhaps the local area has experienced appreciation due to other influences. Without checking comparable properties around this home in its' current condition, no one can say what the current market value should be.