3abad wrote:
Hello, I want to get the Canon 5D mark II "Full Frame". I am too worried about picking up a wrong lens for me. I want a fast lens for sports "Far shooting" and also for making a great portraits with a beautiful bokeh. Which I mean 2 in 1 lens.
I can't afford more than $700 for the lens.

Anyone will be appreciated.
Thanks,
Well, you could also take into consideration the original 5D. But I don't want to change your mind if you are set on the 5D mkII. It's just that the 5D could save you more money towards a better lens.
Anyways, with $700 towards a lens with good quality/performance, here are your options:
-70-200mm f/4L USM. This is the "lowest" end model of the line-up of 70-200mm L lenses. It's priced at $600.00 dollars brand new. This lens isn't as fast as the f/2.8 models, nor does it have any Image Stabilization. But it is a good performer.
That's about it for the less than $700 range from Canon. There are options from Sigma and Tamron, but from the things I've heard, they aren't really as "good of performers" as the Canon.
Another option is to look for some used deals. Some times you might find a 70-200mm f/4L IS or maybe an f/2.8 USM for a little more than $700 or so.
If you are flexible on the body, I suggest you look into the 5D, also full frame. This way you have quite a lot more to spend towards a lens, and you could potentially be looking at the f/4L IS or maybe even the f/2.8L IS.