If you are getting started in the world of SDR, there are some fantastically inexpensive Software Defined Radios out there. 3 popular types are compared in Episode 3 of the 2020 SDR Guide.
You can monitor an amazing amount of signals with these frugal devices, and I highly encourage anyone interested in radio to try one. You will not be disappointed!
I have absolutely no hesitation in recommending either the RTL-SDR v3 or the NooElec SMArt dongles. The RTL-SDR v3 is easy to obtain through Amazon US, but unfortunately not through Amazon Canada or Amazon UK 🙁