Sony memory card pricing hurts them in many ways. It's one of the many reasons I won't buy a Sony camera (no, it's not that I can't pirate pictures or whatever). My favorite shop's prices:

2GB SD card: $8 but I've seen them as low as $6 before.
4GB SD card: $13
8GB SD card: $19
16GB SD card: $33
32GB SD card: $85

2GB MS Duo card: $27
4GB MS Duo card: $35
8GB MS Duo card: $60
16GB MS Duo card: $150
32GB MS Duo card: $250