Now, I don't use capture cards, (PC master race), however I have some friends who use a ton of them. Everyone I have talked to says the Elgato is a great recording device, although some people say you do need a bit better of a computer to use it. Not like a gaming PC, but a $100 laptop isnt going to cut it. It is also going to depend on how serious you are.
As for Mics, just start out buy using a cheap headset mic. This will allow you to get comfortable with audio editing, (that's 80% of Gaming Youtube.) When you feel that you are ready for a new microphone, looking to some USB based mic. I would try to stay away from anything requiring a sound board for a bit.