E.B.
If you're looking for something simple, I used and still use a Fairy Godmother Sling. They sell them at Baylor hospital's Simply Mom's shop. You can order other brands of the same thing online, but it's great to be able to try it on before you buy. The shop is also staffed with nurses who are always happy to help fit you perfectly and explain how to use the sling.
This is just a simple pocket type sling. 1 piece of fabric sewn into a loop and folded in half. When I first saw it I thought it looked flimsy and crazy - I'd never use that. But it works great. I used it to breastfeed, he would sleep in it, I could carry him around the mall... and these days at 21lbs it allows me to carry him on my hip and still have my hands free. Highly recommended.