I listened to some advice I read here on CGN. Everytime you are in a store that sells ammo, check if they have any .22lr. If they have some in stock, buy one bulk box (333-575rnds). Don't horde, don't buy thousands and thousands at one time, don't buy out the store or you are just screwing the next guy (unless there is only one box left but you can hardly call that hoarding). Using this method I've accumulated about 10k rnds in about 6 months even after shooting it regularly. At this point I have enough for almost 2 years so I'll probably stop buying and only replace what I shoot.
Locally in Ottawa for me so far it's been hit or miss. I'd say about 40% of the times I'm in a Walmart, CTC, SAIL, LeBarons, etc. they are sold out (or only have Remington which I don't buy as none of them shoot with any accuracy in any of my rifles).
Of course this doesn't work if you fire several thousand rounds a month. But for me I shoot maybe 250-500rnds of .22lr a month and it's worked great.