Quote: In the least liberal way possible.
Try a shelter ^^
You may not get a full matstiff, but they are a big dog and people tend to be scared of them or cant keep them or abandon them to avoid responsibility. Its possible you could find a potent mix.
Not to mention, Hundred of thousands of dogs every yer are saved from Puppy mills One just got closed down in Pheonix I wana say a year or two ago and they are still finding more around AZ as it is.
There are a butt ton of dogs that could use a forever home at one of these shelters, AND adoption fees are silly cheap WITH ID and spy/neuter.
Just a recomendation, It's where I will be going or when I adopt a puppy here in a year.