Adorama has the Canon 24-105mm f/4L IS USM lens refurbished and in stock again at only $869. These weren’t available for very long the last time they were in stock.
(Compare to $1149 new or $919 + shipping for refurbed from Canon USA).
These come with Canon USA 1-year warranty and include the official warranty card in the box. I’ve bought Canon refurbished lenses from Adorama before and can attest that they are practically as good as new.
Lots of other Canon refurbished deals are here at Adorama.