Canon frequently offers instant rebates on the lenses in the 70-200mm range when buying from authorized resellers. The best place to check for the latest rebate is the 70-200mm page at Amazon, because they are always up to date on the latest Canon promotions.
When you buy your 70-200mm lens, I highly suggest that you also order a UV filter and a Polarizer. These filters not only improves you photos in a variety of ways, but they also protect the glass of your lens. You can still go without the Polarizer, but the UV filter is definitely a must.
Another popular accesory to consider is the Canon EF 2.0X III Telephoto Extender, which effectively doubles the focal length of any L-series lens without sacrificing too much in terms of image quality and sharpness.
You will find mixed reviews of the extenders online, but I’ve personally found that they are a great addition to my camera bag .