I did the math, and as long as you don't wear Bambinos all the time, it shouldn't be that expensive. If you go through 4 Seni Supers daily, it will cost $135.
On a side note, I'm not speaking from any kind of real experience being 24/7, but in the beginning when you're still continent, it seems like it would be in your best interest to wear a heavier diaper to work and wearing something lighter to bed. The logic being that it's unlikely that you're actually going to wet the bed, and so that diaper you wear to bed is largely for show or comfort whereas the diaper you wear to work needs to hold up to some punishment.
For those of you have gone 24/7 for a while, I've heard that eventually, someone will find out. Do you have anything to say on that?