$2.00 CPM for as long as pop-unders window remains open for at least 20 seconds. 1 pop-under per hour. Often pop-ups are multiple. Payments are issued NET30 after the minimum payment threshold of $50. Not recommended.

AdScholar

Pay per pop-up network paying $2.00 CPM for "Giantstitials" ads (full-screen hidden pop-unders). Minimum payout is $25. Constant problems with payments. Not recommended.

Affiliate Target

Offers two programs: multi exit popup program - $6 CPM, single exit popup program - $2-$3.5 CPM.
Minimum payout is $10.00. No special requirements. No feedback.

CasaleMedia

Pop-unders ad network offering industry's highest payouts - 70% of the gross revenue.
Full default campaign management.
Pays Net 30. Minimum payment $25.00.
Your site must receive more than 10,000 unique visitors per month.
Recommended.

ExitFuel

Huge $5.00 CPM on a 24 hour unique impression based on the multiple pop program (generates 2-4 windows).
The payout for the single pop program is $3.00 CPM on a 24 hour unique impression.

Above rates apply only for US based impressions. For each 1000 initial impressions originating from the foreign countries a commission of $0.25 is paid.

Pays both for entry and exit traffic.
Exit Fuel pays once a month with $50.00 minimum. Pays always on time.

Fastclick

About $2 CPM for non-intrusive pop-under ads. One popup per 12 to 720 hours depending on the ad code you use.

You can select advertising campaigns and set up defaults so you can send popunder inventory that they could not sell to other adnetworks.

Fastclick also offers so-called Invue ads. These ads slide in from the left side of the screen and then stay in the middle of the screen until clicked close. Strange, but CPM for these ads is substantially lower.

The program is two-tier, 5% of referred webmaster. Payment is issued monthly once commissions reach $50.
Sites must be in English and receive minimum 3000 impressions per month. Network is selective.
Recommended.

goClick

goClick is a search engine offering pay per popup program. Claims $2.50 CPM for popunder ads. Earnings can substantially hover depending on traffic "quality". So keep an eye on reports. The frequency of the popunders can be set from the control panel. Must be sole popup service.
Minimum payment is $25. The only payment method is PayPal.

PayPopUp

Popunder network with following payment structure: USA traffic - $1.50 CPM, Canada - $1.30, UK - $1, and traffic from other countries - $0.30 CPM. Raw impressions are paid. You have ability to set frequency cap and select popunder on enter (when visitor enters your page) or exit (visitor leaves page).

Payment is sent once your account exceeds $50. Affiliate will be paid via paypal or check in US dollars ($US) or Canadian Dollars ($CAD), 15 days after the end-of-15-days-period.

Pay on time. Minimum 200 page views per day. Accept and quality non-English sites.
Recommended.