Living in a student area, it all depends.
50p for a can in the student’s union, 65p (IIRC) for one in a shop well positioned between university buildings and student accommodation 
Here in the wilds of Arkansas, one can from a vending machine will sell for .55. Some convenience stores will sell the cans for anywhere from .50 to .75 depending on the store. 20 oz bottle sell for around a dollar, but when the new Diet Coke with Splenda appeared, it sold for .55 for a 20 oz bottle. Yay!
$2 Canadian for a locally bottled, odd-tasting 355mL bottle.
At work, Coke from the machine is 40 cents for a can.
You’re getting ripped off!
It’s USD $0.24 here in Tianjin, China.
A can of Coke around here is usually 50 cents or 75 cents.
However, I always get the Sam’s Choice cola. Tastes the same and it’s only 25 cents.
$1.25 per six-pack, on sale, which works out to about 21¢ per can.
Sixty-five cents from the machine at work. We normally wait for one of the stores to have it on sale, four 12-packs for $10, and stock up.
I remember coming back from Europe and being shocked that a six pack of Coke cost more than a six pack of generic beer!
In Las Vegas at the local Walmart, there are vending machines with a plastic bottle of 20 ounce Coke for 60 cents. If you go into the store, a 2 liter bottle is $1.08.
I am really surprised to hear Coke is so cheap in the Arab countries and China!
Maybe we could raise the price as the gas prices rise?
The standard 355 mL can is typically $0.50-$0.65 with $0.50 being the most common and $0.60 also being quite common.
Anything higher than that most people around here would consider a rip off.
$1.00 seems to be the big standard around here for the 20 oz. bottles, though I’ve seen those go as high as $1.50 in a regular vending machine and $2.00 in vending machines placed in certain specialty areas.
Maybe because they want to make up for being seen as a pro-Israeli supplier?
Thinking about it, cans in the UK are slightly smaller, 330ml. Sometimes a small shop gets German cans so you get more for your money.
If I’m at work early enough, a can of Coke is free, since they’re sitting on a table with the rest of the catered food. Otherwise it’s probably a buck in the vending machine-- I never want a coke bad enough to bother buying one.
In Sydney, Australia a 600ml (20 oz) Coke costs AUD$2.80 (USD@2.13).
Depending on what vending machine I use, either $0.60, $0.75, or $1.00.
(Needless to say, I try my hardest not to use the $1.00.)
The places where you’re gouged of course are at movie theaters ($4.50 for a 32 oz), concerts/plays ($1 for a cup) and hotels. I stayed in a hotel recently where the Coke machines were $1.25 (USD) for a can. I drank water on general principal.
I really don’t have incident to buy single cans from vending machines. Single 20oz bottles are usually a buck. Occasionally $1.25.
I do suck them down at home, and try desperately to not buy a 12 pack for more than $2.50 apiece, but will go up to $3 per 12 pack if I’m running out. It’s not uncommon for me to stick one in my bag when heading out to work, either.
We drink Pepsi. 
Only costs $0.22194444444444444444444444444444 a can from Costco.
Coke is about a two cents more per can.
At my work, the 12oz cans are $0.60 each.
In most convenience stores, 20oz bottles are $1.19.
In a grocery store, you can usually get a 2 liter bottle for anywhere from $0.89 to $1.59, depending on if it’s on sale or not.
This is in the NE Ohio area.