Was it 1-800 exactly or something really close? Normally you shouldn't be charged but there are rare cases where it is possible based on the number called. There have been scams that use 1-808 numbers. Those are regular long distance calls to the US.
Generally, you should not be charged for toll-free numbers - the 8xx series, however, there are a number of companies in the USA whose toll free numbers do not include Canada, so ti might be possible that the number you called is long distance from Canada.
You may wish to contact Telus, and query your billing, as Like you, I would have expected a call to a 1-800 number to only consume minutes from my plan.
Reference: FCC Today, there are six toll free codes: 800, 888, 877, 866, 855, and 844.