The cost of email marketing software can range from free to several hundred dollars per month, depending on the features and the size of your email list. Here are some examples:
Mailchimp: Free for up to 2,000 contacts, with paid plans starting around $10/month. Constant Contact: Starts at $20/month for basic features. HubSpot: Offers a free tier, but advanced features require a subscription starting at $50/month.