Firstly, you should note that Fido generally does not price match phones or plans and services. However, there have been occasions where they have offered special promotional plans in response to promotional plans offered by other providers.
When comparing the different services, you should make sure you're comparing similar offerings. For example, second tier providers (ie Chatr, Public Mobile, Lucky Mobile) are often cheaper because they offer different services (ie data at 3G speeds, etc). In addition, some providers might only be regional rather than national. Often, you're just not paying for what you're not getting.
I'm not trying to sway your decision in any way. However, I do believe people should be making informed decisions. There may be differences in service offerings which can be reflected in their cost.
Hope this helps 😀