For what it's worth, most tech employers in the Denver area offer the "Ecopass" as an employer-paid employee benefit, which makes the buses, light rail, and call-n-ride free for the employee.

Without any discounts, the cost for the call-n-ride is $2.60 to the rider, which is a good deal for a door-to-door service, I think. I am not sure where the article got the $21-- maybe the city is subsidizing most of the cost.