Handles subscriptions to your mailing lists and has unlimited autoresponders. Good solution if you have your own server and do not want to pay monthly fees.

For intermediate and advanced users, as it does require some knowledge of PHP.

aWeber provides an offsite system for email autoresponders or ezines. Its a good solution if you will have a large list and do not want to put stress on your own server. They also take great care to get on the various "white lists" to ensure that your email gets though.

aMember no longer officially supports integration with aWeber, since aWeber does not like outside software that add emails automatically. To counter this its necessary to place the aweber signup on the thank you page, or before the signup page. More info on this is available to premium members.

GetResponse is a hosted solution handling your mailing list and autoresponder needs. They can also track your email campaigns, open rates, click thrus, etc.

They seem to be a direct competitor with aWeber, competing on price and service levels. They offer a lower price, with unlimited lists.

According to an email I recieved from them, "You can host and send daily emails to up 10,000 addresses in your account. If you have a larger mailing list, there is an additional fee of $4.50/month for every additional 5,000
subscribers".

1Shopping Cart is not a payment processor directly. They provide additionals services such as autoresponders and an affiliate program that integrates with the membership software and the final payment processor.

You will still need to process payments with a merchant account or another service. * May not work with paypal recurring.