Rafflecopter is probably the best known of the sweepstakes services and has a great reputation. It’s really easy to setup and has good support. Although integration with Mailchimp and Constant Contact is simple, unfortunately a Premium account is needed for email list integration.
In Gleam,email list integration plans start at a reasonable $39 per month. With this Pro plan comes the ability to restrict the competition to a certain location. The Rewards module is great for encouraging people to share your content to unlock a reward. Best of all, Gleam is Australian 🙂
PromoSimple is the least costly of the four services listed for a plan with Mailchimp list integration. A number of people that have attended my Mailchimp training courses however have mentioned that they have found the support and usability of other services better.
Woobox is another widely used and known sweepstakes and giveaway service. Their list integration with Mailchimp is simple and Woobox is really easy to use. They also provide embed code for using in WordPress however I haven’t tried this integration.