http://www.tf2outpost.com/trade/25159262 - was sold for 4 keys+32 refs, at the time of the sale keys were 16 refs so basiclly, 5 keys.

Sale of the amby may look a bit old but is still usable considering last accepted suggestion was 2 months ago.

There's also a buyer for 4.4 keys - http://www.tf2outpost.com/trade/22129988 - changing his price all the time.

There aren't any sellers without pro/spec/basic KS except for one and he's looking for 8 keys, He has a C/O of 6 CS:GO keys.