The Halifax local paper has
Wheels Press and
Jobs Press both appear to of done well. The news paper has command of the local market and has done well of creating a web site to carry its print ads online. The web sites do not need to be pretty or have lots of functionality.
The paid alternatives are
Canada Auto Trader and the free alternatives are
hfx4sale.com,
hfx.forsale and halifax.craigslist.com.
Canada Auto has a local office and its web site looks much better then wheels press.
Today, wheels press has 564 listings and autotrader for Nova Scotia has 301. As competitors I bet they have close to the same users and traffic. Trying to work your way into general online classifieds for cars would appear to be difficult for the province of Nova Scotia. The only way I see getting a good market would to create more of niche.