The DollaTek LCR-T4 ESR Meter is an inexpensive piece of test equipment that can cost as little as £5 (from Aliexpress) or around £8.99 from Amazon.
Powered by a 9V battery, it has just one button to press to get it to work!
All you do is connect up your Transistor, MOSFET, Diode, Capacitor or Inductor and press the button - then it will determine what type of component you have connected and tell you it's value and (if applicable) its ESR rating.
