When Selma got a carpenter's estimate for fireplace built-ins, she went ahead anyway, just not with a carpenter. Using IKEA BILLYs, she built a full bookcase wall flanking her fireplace for £585 (roughly $650), which she says came in at less than half the professional quote, Apartment Therapy reported three days ago. Erica and Chris did the same math differently: their finished BILLY built-in cost $800 total, which Erica described as having "knocked a whole zero off" a contractor estimate,...