We've been using Bantex/Herculite 13oz non-curl blockout banner, lays dead flat, prints great, and is about $.40 p.s.f.. It's got a very light texture to it, customers always comment they like it better than the glass-smooth films we used to use (like PopUp or POSpro) because it has a bit more of a textile feel to it. Not that it looks anything like real fabric, but it doesn't look like a poly film either.