Question about Google's Billing Threshold...

SImilar to say that of Facebook, you know how they bill $25, then $50, then $250, then $500 and so on? I'm tapping into bing and adwords here and was curious as to how this was done..

Is there a set structure in place? I'm in USA, so it's a newly made USA account if that matters.

Thanks in advance bros.

AdWords have similar different payment methods, if you use Automatic Payments you will be billed either:
a. 30 days after your first payment
b. Whenever your account reaches the predetermined billing threshold.

I'm pretty sure that for US accounts, the first threshold is $50.
The threshold only increase if you reach it.

Example;
So if you spend $45 in 30 days, you will be billed $45.
If you however spend $50 in for example 20 days, you will be charged $50 - your threshold will be increased to $200 and a new billing cycle will start.