The STS (http://www.sts.qc.ca/), which is local transportation by bus, offers either a one trip 'jeton' that you have to buy beforehand at an authorized dealer for $3.10 giving you one trip with all transfers necessary or, more economically if you travel a lot, a day pass at $8.50 that either gives the right for one or two adults with children age 12 or less for a maximum of 6 passenger on one pass or one adult alone. Service for the bus ends at midnight; if you need to get around after that, use a taxi. It is not too expensive--about $30 for one end to the other of the city--but if you need one at night, chances are that you are in downtown. From there to the farthest hotel, it would cost you $15.
Taxi service
Phone: 819-562-4717; also, if you have a cell phone anywhere in Quebec, try *TAXI: it will patch you in the taxi service of your region--the cost is 99¢.