http://www.tf2outpost.com/trade/8600581

Now, a list of nice offers.

first offer: "Nuts and bolts frenchman's beret + 5 keys?"

assuming the nutz is 12, (bottom unusual price)=17 keys.

second: "20 Keys pour votre Beret."

aka 20 keys.

third:"23 keys for set: P"

assuming the other parts are one key,

21 keys.

fourth: "okay but would you take 23 keys ? :S "

23 keys.

fifth: "I can do a bud and some items in a couple days if no one beats me by then. "

28 keys.

Not including last one in range as it is tentative/buyer has no bud yet.

Only one link, but rather useful.