I posted about this in the Tech forum not so long ago (See
here), but in a nutshell
I got the Uniden UBC73XLT from Ryda for $150 (See
here) some weeks ago, and for a novice who knows nothing about radio scanning and aviation radio, I got the hang of using it less than two hours after I got it (After reading the instructions of course) and was tapping into YSSY's Tower while watching the traffic from Foreshore Road.
Again, by all means read up on the other units suggested here, but like you, I had no clue on how these things worked, until I got this scanner and it has all worked out for me since then!