I'll go a step further. Don't pay for any sensor, you can make your own resistive sensor from a couple of resistors. The reason they fail is oxidation on one terminal. If you alternate the polarity as you read the sensor, it avoids that problem.
Adafruit has a cheap capacitive sensor (using a micro controller with built in touch sensor circuitry) — but not that cheap. The polarity flip is a clever idea. Well, part of the fun is wildly over-engineering the thing, right?
