The above are the basic elements you need to use an Arduino microcontroller with a sensor:
- Arduino board (Uno or Mega): https://www.arduino.cc/ you can also order these from Amazon
- USB Data sync cable
- Jumper wires
You should be able to get everything above from Amazon. The sensors below are all from Adafruit, but it looks like they are not fulfilling orders unless they are for healthcare professionals. You can find some of their sensors on Amazon. It is best if you can use their sensors because they offer Arduino libraries and tutorials on their website. Depending on the sensor you may also need a soldering iron, but a hot glue gun can also work as long as you make sure the jumper wires are making contact with the sensor outputs.
Below are a couple of sensors based on the projects so far:
Accelerometer: https://www.adafruit.com/product/2809
Temperature and Baremetric Pressure: https://www.adafruit.com/product/992
There is a also a plant humidity sensor: https://www.adafruit.com/product/4026
A similar sensor here on Amazon.