Here are some things to thing about:

Renting: Your rent can go up by as much as 2.5% this year if your landlord wants. (http://www2.gov.bc.ca/gov/topic.page?id=539D67CD1FE548B58B3732CFC299C406). The allowable amount changes every year. But if your landlord is nice, it will be low. Say 1.5% per year.

At this rate, you will be paying 16% more rent per year after 10 years, 35% more after 20 years, and 56% more after 30 years ($1,600/month).

Owning: At current interest rates (2.85%), you'd be paying about $1,115 per month on a $270,000 mortgage, amortized over 30 years. (https://www.cibc.com/ca/mortgages/calculator/mortgage-payment.html).

Historically, interest rates are at an all time low (http://www.ratehub.ca/prime-mortgage-rate-history), but seem to average at 7%. So, if you average 5% over the duration of your mortgage (since you are starting low), you'd be paying on average $1,450 per month. Round this up to $1,500 to be safe.

Now, if you look at historical housing prices for Ottawa Canada (http://www.homesinottawa.com/site/Pages/history-of-average-house-prices.html), you will see that over 30 years, prices have increased by over 350%. That means that your $300,000 house will be worth over a million in 30 years.

Rent Savings: So over the duration of 30 years, you will start by saving almost $500/month by renting instead of buying. However, near the end of 30 years, you will no longer be saving anything. During that time, the money you save can be invested. If you managed to save $500/month for 30 years and got a 7% return on that amount each year, you'd have over $600,000 of savings (http://www.practicalmoneyskills.com/calculators/calculate/howWillMySavingsGrow.php?calcCategory=budget). But you wouldn't be saving that much since every year, the amount you could save would decrease. So lets say it is only $400,000.

So, at the end of the day, it seems like buying is more worth while. Unless your rent never increases, in which case renting and buying are about the same.