[seanwilson]

I use https://www.getharvest.com/. It lets you set up multiple clients, projects and team members, track time and expenses for various project tasks and send out invoices. For invoices, you can track what's been paid and it will send out automatic late reminders. It also has native apps so you can start project timers with a few key presses. There's a free tier that will last you until you get a few clients and the paid tier is cheap.

I originally tracked the above manually using spreadsheets but it's so much nicer having a simple interface to keep track of everything for a modest cost.