I'm going to have to recommend a Labrador Retriever. They're big, but not giant. Don't drool (anymore than a regular dog of course!), don't shed a lot, are excellent family dogs, and protective, are clean, affordable since they usually don't eat a whole lot, and somewhat mild-mannered from what I know about them.
Saints are great, if money is no object. My mom and split the cost, but altogether spent about $70 to buy dog food for our Saint for 1 month. Take that times 12 for a whole year's cost of just food. Of course, mine's still a pup. They do drool, but each one is different in the amount. Mine drools only when she drinks. Easy to groom. Great with people and kids! They are very sensitive though. Dolly, if you look at her wrong, she hangs her head. They are prone to several major diseases too. But I wouldn't trade mine for anything in the world!
My other recommendation is a mutt.
A large, friendly mutt! Usually cheaper to adopt, most have already been spayed or neutered and given shots, and they aren't as prone to genetic diseases as purebreds are. Our first dog was a mixed breed and he was very loyal. petfinder.com. Excellent site for finding shelter dogs in your area. Some are even purebreds! Hope you find the dog you want and your family will love, no matter what breed!