Sometimes very little, sometimes a lot. Hubspot, for example, may charge 10X more than most email marketing tools but they offer an all-in-one marketing & sales platform that includes everything from landing pages and live chat, to a social media management tool and CRM. On the other hand, ActiveCampaign offers an enormous amount of value while remaining one of the most affordable email marketing tools on the market.
Every week, the folks at InVision send a roundup of their best blog content, their favorite design links from the week, and a new opportunity to win a free t-shirt. (Seriously. They give away a new design every week.) They also sometimes have fun survey questions where they crowdsource for their blog. This week's, for example, asked subscribers what they would do if the internet didn't exist.
Email design matters in any successful email marketing campaign. If your emails look terrible, that reflects badly on you, and can make people stop reading. With more people than ever reading emails on mobile devices, it’s important to use a responsive email template so your email resizes automatically whether people are reading it on a phone, tablet, or desktop.