Pippity – EDITORS CHOICE!!! – Starting at $49
Pippity is our favorite pop up plugin for WordPress. The graphics, customization options and features are top notch. It is a bit pricier than other options, but in our opinion, it is more than worth it for the huge conversions that it produces. You can go cheap with a pop up plugin, but remember your goal is to keep visitors on your site, and get them to take an action (optin into your list, downloading a report, making a purchase, etc.
Optin Skin – EDITORS CHOICE RUNNER UP! – starting from $67 Optin Skin offers awesome split testing capabilities that will show you which of your pop ups is working, which might be turning away customers, and which is converting like crazy. We love their interface for this, and their easy to use configurable widgets.
Optin Monster – Starting from $49
OptinMonster is the best lead-generation plugin for WordPress that allows you to create attention grabbing optin forms that convert.
Ninja Pop Ups For WordPress – $22
This plugin is the best value if you are on a budget for your site development. Ninja Popups combines a professionally designed popups to convert visitors on your site/blog into taking an action whether its subscribing into your newsletter, offering a discount/coupon for leaving customers, or locking content until they share you will increase your subscriber count and social signal of your site/blog.
Action Pop – $47
The popup is unblockable since it uses HTML layers instead of actual pop-up windows. A lightbox effect dims the screen behind the popup to prevent them from being distracted by what you have underneath… and eager to fill out the popup form so they can get back to what they were doing.
The popup will appear after every visit, but once they subscribe to your list… no more popups.