Here are some audio interface units we recommend.
Focusrite Scarlett Solo – This is an inexpensive, but top-notch interface that plugs into your computer’s USB port. It has one mic input, which is perfect for voiceovers and anyone who is recording one thing at a time. Price – $109.99
Focusrite Scarlett 2i2 – Same high quality electronics as the Scarlett Solo, but with two inputs (“combo” inputs for mics or instruments) that you can use to record two sources at the same time. Price – $159.99