If all you want to do is listen, remember only one word, ANTENNA.
A lousy radio with a great antenna will run rings around an expensive radio with a lousy antenna.
For CB, a simple verticle antenna will allow you to transmit and listen locally just fine, but it will only offer limited benefit for SWL (short wave listening) on other bands.
You might want to buy an inexpensive CB and put up a verticle - they are not usually very costly.
However, for general coverage and short wave, you can find older receivers on ebay, etc, for relatively low cost. But put up a good antenna! Even a long (longer the better) wire will work well.
Also - if you put up any type of outside antenna, be sure to put in a good ground system - and by that I mean a physical connection to earth.
When using an outside antenna, remember, Mr. Lightning is NOT your friend!!!

Happy listning
Mark - who has had a ham radio ticket longer than he has had a drivers license!