Some people say "just use whatever tools you want, it doesn't matter." But I find it's helpful to see what other people use since that can remove one more decision from the process of getting started.
These are all tools I use myself unless specifically mentioned otherwise. In some cases I have an affiliate link as well as the non-affiliate version. If you have found Less Boring helpful in your career and want to support the site, the affiliate link pays me a small commission. I only am affiliates for services I use myself - otherwise the incentives just aren't aligned!
Freshbooks was one of the first tools I paid for when I started freelancing back in late 2010, and it's been an integral part of my toolkit ever since.
Freshbooks handles saving my client contact information, lets me easily create good-looking invoices, has a nice little system for managing projects and tracking time, and lets me easily collect payments from clients.
That last one is important, as you want to make it as easy as possible for clients to do the giving of money to you part of the interaction. You can easily connect your bank account and let clients pay with a credit card directly through the invoice's web interface.
Their customer service is also top notch! Highly recommended.
They have a 30 day free trial before you have to pay $15 or $25 a month. Also there is a very small (~2%) fee on all payments collected through them.
I consider both of these fees to be highly highly worth the money. Yes you could create your own invoices in Google docs and mess around with checks for payments or (oh heck) build your own checkout form. But you are now a freelancer and a business owner, and it's important for you to consider the opportunity cost here! Also I assume that your hourly rate is a bit higher than $15 or $25.
You can even try it for 30 days free so there really isn't any risk.
Not Affiliate: https://www.freshbooks.com/
Another tool I consider fairly essential is G-Suite, formerly "Google Apps". The G-Suite allows you to set up an email address at your own domain name (they are how I have firstname.lastname@example.org), which automatically signals some degree of competence to clients. You managed to set up a custom domain name and email through it!
It's also a nice way to separate out your work email from your personal email. And you get Google calendar, Google docs, Google spreadsheets, and Google drive for storing files.
Another tool I got set up right away in my freelance career.
The price is $5 a month per user (the basic plan is fine), but since you are indie it'll be just $5 a month. And to all of the programmers out there, don't even think about trying to set up and run your own mail server! Remember, opportunity cost!
Not Affiliate: https://gsuite.google.com/
Note: Setting up G-Suite is a bit trickier than the rest of these tools since it requires registering a domain name and configuring some DNS records. Let me know if this is a topic you'd be interested in me covering.
After being frustrated for years with Skype and Google Hangouts as far as video quality for video calls, I've been thoroughly pleased since switching to Zoom. It seems to be quickly becoming the standard tool for online video calls these days.
And I highly recommend you get comfortable having video calls. Speaking virtually face to face with clients, leads, prospects is a great way to build rapport, and can communicate a whole lot more information than email.
I recommend you have regular calls with your clients to stay on the same page and to remind the both of you that you are both humans.
They have a free version for 1 on 1 calls, and calls with more than 2 people can be up to 40 minutes long. For group calls, at least one person has to have a pro account starting at $15 a month (what I use currently).
Not Affiliate: https://zoom.us/
Never again will you have to do the "what time are you free for a meeting" dance with clients or anyone else. Calendly lets you specify free slots on your calendar and create unique links that let people schedule appointments on any available time. It also integrates with that Google Calendar you set up earlier and will automatically mark you unavailable if you have a Google calendar event for that time slot.
There's a free version to get started and you can upgrade as you get more sophisticated.
Not Affiliate: https://calendly.com/
Trello has been around for forever and is a very solid way to organize projects. If you can get your clients to also use it, it's a great way to stay up to date on everything and let them see at a glance your progress without having to actually write up a status report.
Not Affiliate: https://trello.com/
Mailchimp is what I use for sending out the Less Boring Letters and I've been thoroughly happy with them. They've been around for forever and from the sound of it their company mission is very much in line with mine - to empower small businesses.
I also like that it's free for up to 2000 subscribers, so there's literally no risk in starting up a mailing list. If you get to the point of having more than 2000 subscribers, you can definitely afford the monthly fee.
Not Affiliate: https://mailchimp.com/
Getting a PO box at your local post office is a cheap way to be able to have a separate business address for putting on invoices and so you can remain compliant with email spam laws (you have to include an address in the footer). Then the address isn't your personal home address!