Celebrity dermatologist Dr. Zein Obagi helps us make sense of our skin, tackling all the issues lying between us and complexion perfection. This week, Dr. Obagi helps us save our skin without overspending.

Woman applying moisturizer

Dr. Obagi recommends investing in topical creams that the skin can absorb. Photo: Getty Images

Whether your budget affords $25 each month on skincare or $250, no one enjoys wasting money.

It's often hard to separate the products that work from the ones that disappoint. While the price tag may seem like an indicator of effectiveness there are some effective yet inexpensive products on the market and plenty of useless ones that cost $300-$1,000.

So how do you determine which products are worth the money? Here are some smart strategies:

Know the skin you're in.
It doesn't matter how high-tech a product is, if it's not right for your skin type it won't be effective. Before you shop for skincare products determine whether your skin is thick or thin, weak or strong, oily or dry. Once you know where your skin falls on the spectrum you'll be able to select the products to meet your needs.

Organize and prioritize. If your medicine cabinet is overflowing with old jars and tubes you may have accumulated products that don't work, have outdated technology or may have expired. Get rid of the old stuff and decide what you really need to focus on. It could be wrinkles, acne, age spots, skin laxity, anything, but don't expect to treat all of your skin afflictions simultaneously. No one product does it all so decide what is most important and address that first.

Avoid impulse buys.
Remember the old adage, "you can't judge a book by its cover?" Well, the same goes for beauty products -- packaging means nothing. Don't be fooled by an expensive exterior or deterred by something less attractive. Instead, do your homework. Find out what people are saying about the product and read feedback from actual users on popular shopping sites.

Medicine Cabinet

It's time to organize your medicine cabinet and get rid of old beauty products. Photo: Getty

Look for potent ingredients. Retinol and retinoic acid are the only ingredients that are proven to treat both age-related and environmental skin damage. I like ZO Skin Health Radical Night Repair Plus (1% concentration of retinol) and seldom prescribe retinoic acid in concentrations less than 0.1%. If it's too irritating, apply less frequently until your skin adjusts.

Spend on the stuff that stays.
Rinse-off products like cleansers and scrubs are important, but the active ingredients don't have time to reach the cells in the dermis. Invest in topical creams that the skin can absorb. Under eye, night, and day creams have more time to penetrate, as do serums and spot treatments.

Always wear protection. What's the single most skin saving thing you can do daily? Slather on the SPF! Sunscreen is your best protection again skin cancer and skin aging. There are so many great formulas on the market and you don't need to spend a lot to get the protection you need. More important than the SPF rating is how much sunscreen you actually apply. For starters, one third of the population doesn't even wear sunscreen-a huge mistake that no one should be guilty of in this day and age. The rest of us who do apply sunscreen often don't apply enough-use a full ounce when applying from head to toe, or a shot glass-sized amount. Covering your skin thoroughly with SPF 15 is substantially more effective than a thin layer of SPF 100.

Get kitted out. Kits often combine some of the best products and are priced for value. Unlike many other products that go on sale in one particular season, health and beauty products typically aren't marked down. For the best value look out for the limited edition collections sold around the holidays.

Exercise your right to exchange. If you really want to avoid wasting money, purchase skincare products from a store with a good exchange policy. If you don't like a product, if it's not working for you, return it. I find Nordstrom is very understanding and dedicated to helping customers find the products they need.

To ask the good doctor a question or topic to tackle in a future column, leave a comment below. And check out his website, ZoSkinHealth.com for more skincare information.

Click here for 15 cheap beauty products to stock up on.