Hi Volunteer C,
Yes agree with sumanppc, the cost per conversion is depending on many factors., such as; business vertical, your landing page experience, and the most important is your goal/objective.
In my opinion, beside you have a concern with Cost per Conversion, it is better to understand about the conversion rate. With the conversion rate, you can measure the effectiveness of you conversion performance comparing by the click that you get.
Thanks
@RyanBatchin