The Bosch TPSes are very common. Just like oxygen sensors, most TPSes out there are Bosch or Bosch-licensed copies thanks to Bosch's lead in computerized engine control when emissions regulations started.
They can be found for $20-$100 online, but they are readily available from the boneyard for less. When you get them from the boneyards around here they don't charge extra for the mounting hardware or connectors/wiring (if you don't go overboard -- 1-2 feet of wire) which can be a big time savers vs. buying new.
Here is a datasheet that covers most of the Bosch units:
Bosch - Throttle Position Sensors