While perusing the Continuing Education course offerings of UT Arlington I found an interesting class: "Free Vacations & Make Money Travelling".

I don't mean to lump this in with the book, but wondered how informative this might be.

Further description (though not specific, obviously, since it's just a course overview):
"Would you like FREE vacations or income while you are on vacation? xxxxxx will share how these ideas will make all your vacations FREE and can even become new careers. Learn over 40 different ways to receive FREE airline tickets, frequent flyer miles, mystery shop, fly as an air courier, teach English on vacation, earn FREE tours/cruises & resort nights, write articles, shoot photos, volunteer, or get paid to drive."