I'm a lucky guy. I always buy S. Knives at 0.44 ref, and I've gotten a few.

Maybe on outpost, but on trade servers I can easily get a strange knife for 0.66 refined. Downvoted

Wrong. I get a ton at 0.66

Pretty easy to find for less than 1 refined: http://www.tf2outpost.com/search/45159751

In fact, they're pretty easy to find for less than 0.88:

http://www.tf2outpost.com/trade/5674405 2 rec

http://www.tf2outpost.com/trade/5695524 2 rec

Not to mention the fact that there's hundreds of these unsold at 1 refined lingering for days or weeks in some cases.