I didn't have a c/s so this isn't specific, but I got some lovely hand cream & toiletries and TBH I was so touched that someone gave something to me that I wouldn't've cared what it was, LOL!
But that body pillow idea sounds great! BigW have them on sale atm with a spare pillow case for $30 - just bought one on Sat
If she has a fave movie or tv series you could get it for her on DVD. I watched two seasons of Grey's Anatomy while bfeeding Natty in the first few weeks