Is a monthly subscription available with VerticalResponse for AppExchange?

At this time we do not offer monthly pricing for Salesforce customers. Monthly pricing is based on the number of unique email addresses within your VerticalResponse account and this information does not exist within the current implementation of VR for AppExchange. Currently the only pricing option available for Salesforce customers is our credit based, Pay As You Go plan. Please see http://www.verticalresponse.com/salesforce/pricing/ for more information.