I've had a keyboard made by NMB that I've been using for almost 5 years now. Small, extremely quiet, and I think paid something like $15 shipped to my front door.
Link to NMB Keyboards
For something that you could probably get locally, both Logitech and MS have wired multimedia KB that are pretty quiet. I'm using the MS wired Multimedia KB at work, and it's not bad. I'd just go to your local Staples or Officemax and try out the display models.