grey market .... but then you have the whole warranty issue
L series lenses come with a worldwide warranty. Everything else doesn't sadly.
Offers do come up every now and then. I've had a few cashback deals from Canon on my bodies and flash guns. I managed to get most of my lenses at a decent UK price from retail stores (A couple thought from a decent UK ebay seller)
Should I get something off the grey market then if it has a worldwide warranty anyways?
Some people rail against buying used lenses, but a gently used L lens can be quite affordable. The trick is to find a reputable seller or be able to handle the lens before buying.