Other things to take into account when looking to switch providers, is the coverage that they all provide. Sometimes going with the least expensive one will also give the least amount of coverage, making things very frustrating from a usage standpoin...
The reason I quote TELUS is because Public Mobile is owned by TELUS. When I used to have 500 mins per month and called 1800 numbers, I noticed that mins were deducted from my monthly plan.
According to a TELUS forum, 1-800 numbers are counted towards your plan. So if you call one, it will take minutes off of your plan. You wouldn't need to pay long distance at least, but it will still use your minutes.