This is a plea not to abandon your pet when times get tough.We returned home this holiday weekend to find our neighbor's cat, and her litter box, on our doorstep. It appears as if our neighbor moved out. No note; just the cat. A lot of us will pay dearly for the family pet, and most will say that the expenses are worth every penny -- but clearly, some people aren't so caring with their furry friends. The cost of owning a pet can add up in surprising ways. The obvious expenses include: food, medical bills, pet-sitting expenses, and routine care. After that, you can add on incidentals like toys and treats. Occasionally, you'll pay for your pet to travel with you, pony up for it to live with you, or incur other unexpected "pet fees."