Making your Own Icon Font (for free)

So the simplest approach if you just want to combine only the icons you want from existing free fonts is to use Fontello

The next step up with a similar approach is Fontastic. The big advantage here is the ability to add your own vectors.

Now if you want to go full out Inkscape has your back via a few quick built in steps:

• OBJECT → FILL AND STROKE
• OBJECT → ALIGN AND DISTRIBUTE
• TEXT → SVG FONT EDITOR

and there is of course a really great article to walk you through the whole process: