Mailchimp
If they want to utilize Mailchimp SMS/Texting, there is a $20 add-on to their bill monthly for 1000 credits or $25/mo for 2500 credits. Credits do not rollover each month, and there will be a need to either get numbers at subscribing/sign up and/or email all current contacts to have them opt-in to SMS. Most text messages will require 1 credit to send, but any text with a pic or video in it may use up to 3 credits per contact.
This process requires our team to submit an application to Mailchimp. The number is random but potentially local to the client. The process takes up to a week to set up.
EZ Texting
EZ Texting allows up to 500 contacts for $25 a month. It also includes up to 500 credits with each additional credit costing $.03 per credit. Some text messages use one credit but most photos/video text messages will require 3 credits per contact. The pricing triples for 500-2,000 contacts.
Constant Contact
For Constant Contact SMS Messaging, the pricing for Premium Accounts is: 500 credits included per month. All other monthly plans do not include texts and cost $10 add-on pricing (base price).
Other:
Network for Good allows text message communications. Our team is unsure of the pricing at this time.
Virtuous has an SMS option.
Givebutter has a texting feature on their Plus account for around $30 monthly.