Question

I've been looking around for a basic open-source/free self-hosted CRM system that does basically this,

Let's say I go and try to sell a product to a business and they say "We'll think about it". I want to be able quickly to input their email, name, and so on, in some kind of a campaign form that will start to email them constantly. Like on the first day, an email will be sent to them saying, "Hey, we popped in today, here are the great features of our product..." And then email them again on the third day saying

Answer 1

A (web-based) Twitter client like Tweetdeck, Hootsuite and many others alike could do this for you. Maybe a direct tweet feels less intrusive than a daily e-mail request ... ? ;-)

From my personal experience I know you can schedule tweets upfront. I passed a Hootsuite exam a while ago and tested this functionality. But I would not try to sell products the way you described in your question.

If a customer says "I'll think about it" you just have not convinced him / her yet. It is a different way of saying "no" to you. And that conviction or belief in your product will not grow if you start informing by e-mail / direct tweets of whatever afterwards. On the contrary.

Why not try to persuade a prospect differently? If one says "I'll think about it" you might challenge him/her right away and say "I am sorry I have not convinced you up till now. What is needed to strengthen your believe that this product offers you the advantages today". There's many possible sales techniques that will work a lot better than asking for the same rejection over and over again. Among my favourite salesmen with great online / off-line courses/book, tips and tricks, and humorous (but oh-so-true) one liners: Zig Ziglar and Jeffry Gitomer.