I don't think the care of Dogos is any more or less expensive than the care of any large purebred dog. Having said that, though, it is expensive. Food, vet, shots, training, heartworm cookies, fuzzy toys, jolly ball, and so on and so forth. You really want to think hard about buying or adopting any dog if you are going to have give up eating for a couple of days to take him to the vet. Or if you have to question whether or not you can afford at least basic obedience training.
Food is just a drop in the bucket.
Dogs are wonderful companions, but they are also an expensive hobby. You are looking at a similar kind of expense. Please understand, I'm not complaining, and I wasn't surprised, since Thor isn't my first large purebred dog. I knew what I was getting into, and I was prepared for it, and I don't begrudge a single dime I've spent. However, if affordability is a real issue for you, I would recommend you look in another direction.