Pay the low minimum price for any keyword. Or pay more to get more exposure. Either way, Google's Discounter ensures you pay the lowest amount possible to keep your position.
Let's say there are just 3 advertisers competing for "widgets".
A's max bid is $2.00
B's max bid is $1.00
C's max bid is $0.05
If somebody searches for "widgets", and all 3 ads are selected to be displayed, who pays what for a click?
Theoretically it can be worked out as:
A: $0.07
B: $0.06
C: $0.05
...but I don't think it happens like that, so what's the deal?