What kind of terrain are you talking about hiking in on? If riding isn't a prerequisite, all you want is a critter for company and to haul your animals out that's a pretty easy find. A mule broke to pack and not ride will be cheaper than one to do both. But that being said, if you're not able to dally the lead rope around your horn and drag if necessary to get him started, ...
As you can see by the thread so far there are many many variables. But either way you go, if all you want is to pack not pack/ride, that should make your options cheaper and easier. Training one to pack is a much shorter, and easier and therefor cheaper option.
Just my $.02
