Fonts and Barcodes in Microsoft Office
First, let's clear this up: Fonts used in Microsoft Office are not a component of Microsoft Office, but of Microsoft Windows. While some applications may install fonts for you, they get installed to Windows, not the application in which you use them. I am talking only of Microsoft. Other applications may work differently.
Barcode Fonts
A barcode is nothing but a number that's formatted using a barcode font. Usually, a barcode font has a specification, so you'll want to know what specification is required by your barcode scanner. Then just type that specification into Google, and you'll surely find a font out there to use; maybe even a free one.
So, suppose you're doing a mail merge and need a barcode? Just select the merge field that contains the barcode number and format it with the barcode font.
Installing Fonts
There are tons of free fonts on the Internet; so many that you shouldn't have to pay for them.
To install a new font, just download it to your desktop. You'll probably want to close all your applications first. Doing so should ensure that when you open the application, the new fonts will be available.
Open your Control Panel and go to the Fonts folder. From the menu, choose File Install New Font. Browse to your desktop by double-clicking, in this order: C:\, Documents and Settings, Your name, Desktop. Leave the "Copy fonts..." checkbox checked. Select any and all fonts you want to install and hit OK. After they're installed, you can delete the fonts from your desktop.