how much should it cost to replace a v-belt?
on 1999 Audi A6 Quattro

The power battery light came on, then the power steering went out, manual says it is most likely the v-belt, and upon opening the hood can see the broken belt

Asked by for the 1999 Audi A6 Quattro ---click on this link, select service and go to the maintenance section, the info is all there.
1 more answer
What's a "power battery light"? Don't start it or drive it, obviously. Big trouble if you do. A V-belt (timing belt) is cheaper than an engine and you probably would want to change the thermostat at the same time. Manual also says to change the timing belt at regular intervals (90K -120K?).