As far as I know cable boxes are only available from your cable company (legal ones anyway). I believe that most will only rent (of course, in a year you have paid for it) but there may be some areas and states that require them to sell it to you outright.
Cable companies are paranoid about theft of service and this is one way to help control it.
Direct TV or Dish network receivers (as provided via satellite) can be purchased from any number of places including Radio Shack just to name one. You will have to have it authorized by the service provider after you hook it up meaning that you will be paying for the programming.
-Hal
[This message has been edited by hbiss (edited 12-21-2004).]
