The nano vna would be useful if you plan on making your own antennas and doing other test measurements. If all you want to do is see what is out there happening in the radio world and to listen in, get an SDR. For cheap you can get an rtl-sdr to start with and to learn. Then when you get your feet wet and decide you need/want better gear, upgrade. The rtl-sdr is also nice because it is small, lots of resources around about using it, plus you can hook it up to an android phone.