I would like to know about paying for adwords by paying for conversions. I have not been able to locate the information and requirements. I called the help desk and they offered to email me the directions to find it, but they did not follow thru.
What you are looking for is not CPC (cost-per-click) but CPA (cost-per-acquisition). A conversion is sometimes also called an acquisition.
This link describes the basic concepts of CPA:
This one explains how the AdWords Tool (Conversion Optimizer) that you'll need works:
Generally, you got 2 option CPC ( cost per click) & CPM ( cost per thousand impression). It seems that you are looking for CPA ( cost per acquisition) which is not enabled for new account.
To avail this option, your account need to have At least 15 conversion in past 30 days and It getting converion on regular basis. CPA use historical data for bidding. If you don't have conversion data then you need to setup conversion code on your website or you can use Google analytic. ( search more on this topic).
When you account is eligible for CPA, then you can find the option enabled in Capmaing setting tab under bidding option. There you can set a maximum amount willing to pay for a converions. You can read more here - http://support.google.com/adwords/bin/answer.py?hl=en&answer=2472713