Buying fancy serums and anti-aging ointments can get pricey, but beautiful skin shouldn't be a luxury.

“Skin care doesn't have to be expensive to be good,” says dermatologist Dr. Debra Wattenberg, a New York City cosmetic dermatology specialist and founder of her own practice, SkincareRX.

“Some of my favorite products come from the drugstore. The ingredients determine the efficacy, not the price, so don't be fooled by expensive products that contain beautiful packaging and fancy fragrances.”

Dr. Wattenberg shared where to buy the best products and how to prep your skin for the changing seasons, all with your budget in mind.

The 3 Skincare Essentials

On top of a healthy diet, regular exercise (which when you sweat, clears toxins from your pores) and adequate sleep, the key to beautiful skin is having the right basic products. According to Dr. Wattenberg, any good skin care routine should include:

1. Facial cleanser
2. Sunscreen
3. Moisturizer

There's no need to shell out $150 for one ounce of Creme de la Mer, either. Dr. Wattenberg's recommended brands include Neutrogena, Oil of Olay, Cetaphil and Aveeno. If you have a little more room in your budget, she also likes upmarket brand La Roche-Posay, which drugstores such as CVS and Walgreens sell for $28 (for 1.35 ounces of moisturizer).

If your budget doesn't leave extra room for new skincare products this month, make the most of basics you already have. “Vaseline ($1.50) or Aquaphor ($6) can be used to cure dry cuticles, heels and elbows as well as chapped lips,” Dr. Wattenberg says. (Check out 13 more healthy and cheap beauty replacements.)

Other ways to save? Try buying your favorite moisturizers and cleansers in bulk, and try to buy face creams with pump dispensers to avoid bacterial contamination from touching the mouth of the bottle with your hands, making your product last longer.

What to Look for in Your Skincare Products

Oily or acne-prone women will need something different from women who have dry skin or are developing wrinkles. Dr. Wattenberg loves 2-in-1 products, like combined sunscreen and moisturizer, because they save time and money.

“The one exception is foundation with SPF,” Dr. Wattenberg warns. “While it's a great product, most people don't apply enough to get the SPF they need, so I usually recommend a moisturizer with SPF in addition.”

If you are buying anti-aging products at the drugstore, look for ingredients that target your issue, rather than falling for package advertising. “For example, don't buy a product just because it says ‘collagen boosting.’ Look for ingredients like retinol, vitamin C or hyaluronic acid,” Dr. Wattenberg says.

If you're experiencing one of the four common skin problems below, look for these ingredients in your products:

If you have a specific skin issue, are trying the regimen above and still not seeing results, consult a dermatologist, Dr. Wattenberg suggests. You may need prescription versions of the treatments you're using.

Transitioning Your Routine From Summer to Fall

As the season changes, your skincare routine should, too.

During the summer, Dr. Wattenberg recommends skipping moisturizer in the morning and just using a sunscreen if you are experiencing breakouts. You can also try using oil-free products. That said, these tactics can dry out your skin as you get into the winter months.

As the weather gets colder, you may need to reverse your routine. Use moisturizing creams that contain oil to hydrate your skin in the winter months, and consider using a humidifier in your bedroom to combat the dry air. You may also want to avoid products with alcohol, salicylic acid or glycolic acid, because they can cause dry or cracked skin.

There is no set seasonal deadline for changing over your routine--just be mindful of the environment and how your skin is responding.

Most importantly? Even when the summer ends, sunscreen is still a must year-round for healthy and youthful skin.