Selling your house without a real estate agent can be a great way to save money, but only if you do your research and are willing to put in more of your own time.
While you won't pay commission when going with a for sale by owner option, I wouldn't consider the entire commission as money saved. This is because you may have to lower your price slightly lower than other comparable homes, and if you don't you may have to deal with some lower offers. But having this extra room to lower your price isn't a problem, it actually gives you a competitive advantage. As an example, if your commission would have been $15,000 you could reduce your price be $5,000 or even $10,000 and still come out ahead.
So what price should you be setting? Have a look at similar houses on Realtor.ca and also look at the listings on sites that help you sell on your own like ByTheOwner and ComFree. Don't just look at prices, but also information like how long it's been on the market. If the same house has been for sale for awhile then keep in mind that it may not be properly priced.
One of the downsides can be a lack of exposure from not being on MLS, not only for the people who won't find your house on Realtor.ca, but also because real estate agents are very unlikely to show their clients your house. The other downside is availability for showings. If you're only available late at night and on weekends, then you may miss too many sale opportunities.
With a down market, a relatively cheap townhouse, and no previous experience with the real estate process, I did use a realtor for my sale. While we don't plan to sell again for a long time, I might try selling my house myself if it's a sellers market when that time comes. Have you sold your home without a real estate agent? If so, leave a comment and let us know about your experience!