Definitely! when I was first consulting I created all my invoices in OpenOffice doc files, and then emailed them out. I kept track of everything I'd sent out to clients on a spreadsheet. It was worth it because it was free. I didn't have many clients and was just starting out. Wanted to keep my expenses down.

However, after a few years I used FreshBooks, which automatically built an invoice for me. I could run reports easily. I could send the invoice. I could even accept payment via credit card.

It cost me something (I don't remember what it was, but it was under $50/month) and saved me so much time. (There are many competitors to FreshBooks and I'm sure each of them would have done the same.)

That's the tradeoff. Most things can be done for "free" if you count your time as having zero value. That is very rarely the case. It may be a good idea to minimize $$ out the door as much as possible when you are starting, but in a while (even if it takes you years, like it did for me) you'll learn to trade money for time using specialized tools.