I don't mean to be contrarian but if you want to be successful as a independent developer (I have been for almost 15 years now) and you are looking for a CRM you are off the rails.
CRM systems are for the most part, for companies or sales individuals who need help managing the number of contacts they have at any given time and ensuring they follow a structured interaction pattern.
I know about a dozen people like me, some of whom float in and out of full-time gigs and consulting and others who are years or decades into the independent consulting arrangement. Not a single one interacts with a high volume of customers. At any given time I have two or three I interact with and maybe one in the pipeline. If I make contact with new potential customers I create a contact record for them in Outlook/Gmail/Whatever and record any extraneous details in the notes section. That is all, if you need more than that I question the approach.
ps - Another tip. 'Freelancers' are cheap and not serious, 'consultants' or 'developers' or 'independent developers' take home the big checks. Just a perception thing.