Why would you want the mule? If it's just going to be hanging around doing nothing, probably not worth it. They eat a lot and are expensive to keep up, with foot trimming, shoes if needed, vaccinations, deworming, tack, routine maintenance and emergency vet bills when they do something stupid and get hurt (having a vet drive out to put some stitches in a leg could set you back a few hundred dollars!) which seemed to happen at least yearly with every horse I have had.
Why is the mule being offered? It may be that they just don't want it anymore or can't feed it and there is no market for equids where you live...lots of people are giving away horses/mules/donkeys here or just setting them loose in the streets because feed costs too much and they lost their jobs. Make sure he is healthy. Find out how old he is. Go to where he is and handle him yourself, see what he is like. A mean mule is dangerous, they can be much more aggressive than horses, and are very good at kicking. A well-aimed kick from those back feet can kill you. Mules are loud, too. They will wake you up at breakfast time--their idea of breakfast time. Maybe annoy the neighbors. If it is a male mule, make sure it is gelded (neutered). Many people don't geld males because they are sterile, but they still have testosterone, and that can make them an aggressive, bad pet if they are not trained right from the start. Once they are over a couple of years old, gelding won't always get rid of the problem behavior either, so don't think you could get him intact and have him gelded to gentle him if he is already set in his ways.
All that said, mules can be great, enjoyable animals. Just make sure you do your research first, for your sake, and the mule's.
