Spa prices don't always include add-ons (an enzyme peel here, an oxygen blast there) offered during the course of the treatment. When you book a facial (body services, like massages and scrubs, are less likely to involve extras), ask if it's all-inclusive. More and more spas, like Remède (in New York City, San Francisco, and Aspen), let you book time (30, 60, or 90 minutes) and then customize the facial for your skin—with no extra charges for any of the creams or masks they deem appropriate. If you're going to a spa that has a more à la carte menu, describe your skin concerns when you book the appointment, and ask what add-ons (at what prices) the aesthetician might suggest once she sees you. Then decide ahead of time how much more (if anything) you might be willing to tack on to the base price. Once you're in the treatment room and the aesthetician starts prescribing an extra this or that, you can announce up front what your budget is. "Just be forthright and say, 'I want the best for my skin, but this is how much I can spend today,'" says Jaeger.