It dependson what the dish is, and where it is pointed.
If it is a smaller DBS type dish, all it has is encrypted channels, so your only option is to get their receiver and subscribe to receive signals that dish is picking up. Not paying for channels (packages most likely) is not an option with such a dish or receiver system, unless you are okay with nothing, or the provider info channel at most.
If it is a 30" or larger linear Ku dish, you have a much better chance of getting non-encrypted programming which is free to receive, although I warn you most of the channels on pay systems are not there at all. What channels you get depends on what satellite it currently is pointed to, or you care to repoint to, and also to a certain degree the capablilites of your receiver of choice.