Katherine Boyle / The Washington Post

We Americans have always loved our dogs, but a dog has never had it this good. The average cost of man’s best friend is somewhere between $10,000 and $14,000 over the course of its life, according to the American Society for the Prevention of Cruelty to Animals.

Consumer Reports says that Americans spend $20 billion on cat and dog food annually, making it the biggest, most predictable expense during your pet’s life.

The cost adds up quickly, and yet many people don’t factor in how pricey it will be, particularly if you choose to feed Fido a gourmet brand.

According to a 2011 Consumer Reports study, dog food can average $36 a month. It is the biggest ongoing cost of owning a dog.

But you can save money on this expense if you’re using coupons, buying in bulk and, most important, buying less-expensive food.

We looked at some tips for shopping and did our own price comparison.

Here’s what you can save over the course of your dog’s life if you budget his or her meals well.

Know what you’re buying

What separates premium dog food from regular, everyday nutritious food? While we didn’t evaluate nutritional value of food for this column, it’s important to note that Consumer Reports says that there’s no legal definition for “premium” blends or strict requirements for nutritional quality.

Although some pets have special needs and require certain food, most pets are fine with a blend that says “complete & balanced” or meets the minimum requirements of the Association of American Feed Control Officials. If you’re on a budget, ask your vet about less-expensive varieties. Always consult your vet when choosing your dog’s food.

Prices vary dramatically

Even when types of dog food don’t necessarily vary in nutritional content — although they may vary in flavor — there’s a wide range of prices among those that meet the minimum health requirements. According to Consumer Reports, Ol’ Roy sells for 34 cents a pound at Walmart. At the other extreme, Purina Chef Michael’s Rotisserie Chicken flavor sells at PetSmart for $2.22 a pound — 6 1/2 times more expensive than Ol’ Roy.

Before you adopt

Pet food is an ongoing expense that you’re likely to have for a decade. Dogs are creatures of habit, eating what they’ve eaten before, so the foods you buy early in your dog’s life matter. Start your dog on store brands or moderately priced varieties. If you start your pet on the premium brand, they may not be willing to switch to lesser varieties.

Buy from big-box stores

Consumer Reports sent secret shoppers to 21 retailers and found that Target and Walmart often have the lowest prices on dog food, while supermarkets and specialty pet stores — including such retailers as Petco and PetSmart — tend to have higher prices. Also, Costco and other warehouse clubs tend to have great deals on dog food.

Don’t shop online

Consumer Reports determined that prices online were much higher. Its 2011 study found that online sites were 50 percent higher, before shipping costs. Skip the convenience of online shopping and just pick up the 50-pound bag yourself.