A nice mechanical one $64
Amazon.com: Intermatic EH40 240-Volt Electronic Water Heater Timer: Home Improvement
A less nice mechanical one $53
Intermatic T104 208-277-Volt DPST 24 Hour Mechanical Time Switch - Amazon.com
$55
Amazon.com: Intermatic WH40 Electric Water Heater Timer, Grey: Home Improvement
a cheap one at only $41 but it's not high enough amps for my tank. Technically it is but I'd prefer the 30 amp breaker to be the lowest rated component.
Intermatic WH21 Electric Water Heater Timer - Amazon.com
this is just checking amazon. If anyone knows of a cheap 30-40 amp 240V relay that can be switched via arduino I'd love to know about it...