I live in Saskatchewan too. My family has only boarded our horses once, then we moved to an acreage. But that was at a city-owned stables, so it would probably be different for you.
I have looked at many website of stables here in Saskatchewan, and I've seen the prices ranging from $150 - for outdoor board to around $400 - for indoor at nicer places with extras like arena access and all that extra stuff.
Here is a link for some of the stables/farms in Saskatchewan, not all offer boarding but you can look around for one near you. Horse Farms in Saskatchewan