If you thought Costco (COST) was already expensive at $988 a share, Bank of America has some news for you. The bank reinstated coverage Monday with a Buy rating and a $1,185 price target, one of the more aggressive calls on the stock right now, arguing the warehouse giant still has 20 percent upside from here. Shares jumped 2.8 percent to $1,012 intraday. Not bad for a stock that has already been outrunning the S&P 500 by 15 points this year, even as banks cratered and tech stalled out. Especially given ...