From the corner of Colorado Boulevard and 8th Avenue, Trader Joe’s appears to be the best thing that’s happened to grocery shopping since sliced bread. In car after car, shoppers have been funneling in and out of the parking lot at the Colorado Boulevard location since it opened Friday morning. Lured by the promise of low prices and unique items, Trader Joe’s shoppers flocked to the three new locations Friday. “The frozen products are a working mom’s dream come true. They are usually less than $5. Rip open the bag, throw it in the pan and you have dinner,” Katie Houlihan said Friday while waiting in the checkout line. Houlihan, a mother of three, had been shopping at Whole Foods Market, but will now be a Trader Joe’s regular. “It is the best ...