I plug directly into my Mac with just a 1/4">TRS 1/8" cable, works like a charm. At first I tried a special 1/4">USB instrument cable but that didn't sound very good and created some issues with compatibility. Try the simplest method first before buying something unnecessary.
BTW, GarageBand is a great recording program that is included with Macs, just saying, if you still live in Bill Gate's world.
