This girl knows how to shop! I would be more than happy to spend your gift certificate for you.
There are several options on Sony Style for lower-priced items.
For something practical, do you need any recordable media for file storage? They have memory sticks, USB drives, CD / DVD / Blue-Ray disks. Need a new clock? Portable radio? All the major categories have an accessories category. Need any cable for your audio home theater or TV?
For something more fun, they have Movie DVD's starting at $10. PS3 games start at $30. Headphones to listen to music on your ereader?
Looking for a holiday gift for someone? Digital photo frames start at $60.