Logitech Wave Keyboard for $29.99 shipped.  Here is a screenshot for your reference.  This keyboard has a wave key design that has contoured wave-shaped keys and a curved profile.  It also comes with a cushioned, contoured palm rest and programmable F-keys.  Note that it comes in OEM packaging, which means no pretty retail box and marketing materials but is otherwise identical.  Most places sell it for $35 or more.