Larry Morton is the go to guy at Tomalco Track, google them. He sells S scale Microengineering, flex or rail, and sells turnouts. A 3 ft stick of flex is about $6.80, compare that to Atlas O at about $16 a stick.
Customtraxx of Indianola Iowa has turnouts you won't believe (they're beautiful!) and around $42. Compare that to an Atlas #5 or 7 in O at around $90 - $95 bucks!
And...S is 4ft 8 1/2 in. Between the railhead as God ordained, not 5ft, as in O!
Welcome aboard, should you decide to come our way!