For leather flats I keep a look out at wittner, witchery, tony bianco, DJ's and myer. They always have things on sale, it helps buying out of season too (which isn't much help at the moment but good to keep in mind).

I tend to wait until the end of the season then buy simple shoes that are trans seasonal and don't date, then buy cheaper shoes (like rubi) for things that are "of the moment" and will date.