Each ad format has different minimum and maximum rates.
You can place your bid in accordance to the suggested rate card, Which you can also find on the panel: http://ad-maven.com/Recommended%20Rate%20Card.html

Push Notification CPC:
Minimum: 0.003$
Maximum: 2$

Popunder:
Minimum: 0.0002$ (Translates to 20 Cent CPM)
Maximum: 0.05$ (Translates to 50$ CPM)

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