But there's also time savings that should be factored into that equation. When I worked downtown, the bus trip from Morningside took roughly 35 minutes. Add to that the fact that I had to be at the bus stop at a particular time (and after 8:15 AM my goose was cooked because that was the last bus downtown). I could get downtown on my bike, riding safely at a reasonable pace, in 25 minutes. Given the additional 10 minutes it took to get from the stop downtown to my office, riding my bike gave me a minimum of 40 extra minutes a day (and this doesn't account for the extra time saved by not having to exercise after I took the bus home).
Given all of that, I'd be willing to spend $10-$20 over the cost of a bus pass each month for access to a shower.
That is, if I cared about showering when I got to work