Well... we all know or should know, that we need proper licensing when using fonts, whether it be personal or commercial licensing. Obviously, Personal use is normally free, but not always, and is for YOUR use only (not to sell or use to sell products). Commercial (normally has a cost) is for use of the font/graphics in products, items, banners, etc. You want to make sure, whether it is personal or commercial, that you also download the licensing terms and read through them to make sure you are abiding by the law. Designers have different policies, ways to purchase their fonts/graphics, and ways you can use their fonts/graphics.
Here are a few affiliate links:
(I'll add more as time goes on)