Bed Bath & Beyond, the dominant big box home furnishings chain, has agreed to buy rival Cost Plus Inc., which has 259 stores including 14 in Gulf Coast, central and north Florida. The price is $495 million, or $22 a share, which amounts to a 22 percent premium over the Tuesday closing price of Cost Plus. The acquisition came after a test in which Cost Plus, which trades mostly in home decor, set up a specialty foods department inside select Bed Bath & Beyond stores. No store closings or job cuts are forecast. Bed Bath & Beyond operated more than 1,100 stores in 2011 with sales of $9.5 billion.