At my local flea market used train shop, things are generally priced very reasonably.
But, last week I saw that they had a basket full of used Fast Track, straights and curves, and every piece was marked $5.00.
Just me, but I thought that was pretty high, especially since the well-used Lionel tube track is often priced at eight pieces for $10. (They do have rust on them though.).
Mannyrock