This post was written and submitted by Louis Lazaris, the publisher of Web Tools Weekly and Tech Productivity. One of the biggest challenges I’ve had with my primary newsletter is how to grow while maintaining a proportional profit. I’m currently using MailChimp as my email service provider, and I’m on a legacy plan (which is good), paying about $125 USD per month. Web Tools Weekly currently has about 11,700 subscribers, almost all of which has…