I've seen some really good prices at homebrewing.org for kegs. I got bit by the same bug as you so the other day I was visiting my LHBS and I asked Chris about kegging. He was very helpful and told me a lot about kegging and answered all my questions. I ended buying a keg, lines, regulator and picnic tap. This is a basic one keg starter system. You can order online if you want to, but when buying used kegs, I think I like looking inside and seeing what I'm getting. Unless you're buying new kegs, I'd check out your LHBS.