It is possible to use free professionnal fonts, with a commercial use licence.
How to find free fonts & webfonts With commercial licence
Here are the websites where you can download free fonts and receive email alerts about new fonts. Most of those fonts are given with a commercial use licence. So you are free to use it for business purposes!
A weekly selection of free products even for commercial use (sign up to their newsletter to stay up to date) and always at least one font!
And of course, if you need to use a webfont, there are dedicated websites :
This post will be updated regularly. If you have suggetions, please post them in the comments! Those might be added after I check them out.