The "A" stamps are worth $0.30 in Canadian postage for domestic use.
Technically, they should only be used on domestic mail and not for mail destined to the USA or overseas.
Someone should ask : Why "A" stamps?
At the time (1981) Canada Post decided to raise the cost of first class domestic mail by 76%. That is right: 76% from $0.17 to $0.30
However, the Canadian government was slow giving approval so Canada Post printed "A" stamps just in case the government turns down their rate increase. They were issued at the end of December 1981.
Once the rate was approved, Canada Post moved quickly to print $0.30 stamps, eventually issued in May 1982..
(Might be a stupid boring question but thought Pierre might know, and I'm curious)
This increase from $0.17 to $0.30 happened before I existed, so in other words no one would've used only a 0.20 stamp for domestic postage back then. How come there are still a lot of 0.20 stamps with discount postage lots (very fancy looking ones too, some said it's for Montreal Olympics)? And these stamps were printed at 1976... as you said, the price increase happened in 1982, so the domestic postage in 1976 must've been the same or cheaper than 0.17. So, what were these 0.20 stamps doing out there back then? When I was looking at the lot I bought, I just assumed that the year on the stamp = the postage cost for domestic mail back then. Apparently it's not necessarily the case.
Just curious, that's all 
The $0.20 stamp was used for international (overseas) mail way back in 1976. In those days, you would find Christmas stamp sets made of three stamps: $0.08 (domestic), $0.10 (to USA); $0.20 to overseas.
Ah ha. That makes sense. I guess that's why in the stamp lots there are some "single" stamps instead of 4 together. Those are probably broken apart from these kind of mixed dominion sets to be separated into different lots.
Oh how I wish I can send a letter with only 20 cents overseas now... it's $2.50 min to set a letter overseas now. 12 times from... 40 years ago, and we're getting another rate increase next year 
@recped wrote:International or USA or Packages
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Haha! Those of us who are over 50 had this answer right at hand! I guess I've just dated myself
It's amazing how knowledge of the simple answer to such things can be lost in a generation or two.
Actually 'zeechan's' question reminded me of an incident that occurred about 10 years ago in an office where I was working. The office manager asked a young student who was doing "odd jobs" for the firm for the summer to clean out the fridge in the lunchroom. The student took one look at the fridge, then ran back to the manager to say: "There's ice everywhere inside -- how do I get that out?!"
Need I add for those of us over 50, that the fridge was not frost-free, and the student was instructed to simply unplug it and wait to clean up the remains of the ice. Oh, right.
In the same vein, it makes me wonder whether all those fine old colourful sayings in English about the lowly penny will make no sense ("cents"?? LOL) to anyone under 20 in a couple of decades. A penny for your thoughts? Pennies from heaven? Penny wise but pound foolish? Penny candy? Cost a pretty penny? Penny ante? Spend a penny? Penny-pincher? Turn up like a bad penny? The penny dropped?, etc. etc. etc. Huhhh??
OK, sorry, now I'm babbling...
