New York’s insiders call it “masstige” — mass market plus prestige — and it’s not always a compliment. But the recent deluge of high-end designers turning out low-cost lines through big-box partnerships makes for clothing that’s accessible and relevant. Target launched GO International in January 2006, bringing celebrated designers to the masses with 90-day limited-edition lines. For stylephiles on a budget, it’s the gateway drug to eventually owning a “real” Luella Bartley or Proenza Schouler. Other retailers are finally catching on, with low-cost outlet Steve and Barry’s launching lines by Sarah Jessica Parker, Amanda Bynes, and athlete Steve Marbury. Kohl’s launches Simply Vera (Wang) this month. They might not have the magic touch, however. SJP’s line, Bitten, was savaged in the fashion blogs. A visit to our local Steve and Barry’s produced the same opinion — the line is woefully unoriginal and screams “discount.” (Steve and Barry’s own clothing, however, was fun, fresh, and cheap — load up on graphic tees and girly cargo pants for weekends.) While other retailers are working it out, keep your eye on GO for fall — Londoner Alice Temperley’s black-and-white line of graphic knits and demure mini-dresses will solve your LBD dilemmas just in time for the holidays.