Anyone thinking about their CFL team building a new stadium should take a look at the cost of building the most recent MLS stadiums. Although they are not exactly the same configuration as CFL Stadiums, they are a better configuration for pricing comparison than NFL stadiums.
2010-Red Bull Arena (New York Red Bulls): $180,000,000 (25,189 seats) for $7,145 per seat.
2010-PPL Park (Philadelphia Union): $120,000,000 (18,500 seats) for $6,486 per seat.
2008-Rio Tinto Stadium (Real Salt Lake): $115,000,000 (20,000 seats) for $5,750 per seat.
2007-BMO Field (Toronto FC): $63,000,000 (21,800 seats) for $2,900 per seat.
2007-DSG Park (Colorado Rapids): $110,000,000 (18,100 seats) for $6,077 per seat.
Any CFL team building a 30,000 seat stadium should reasonably expect the price to run from $120,000,000 on the low end to $195,000,000 for one with more amenities. A 35,000 seat stadium would run $140M-$230M.