Yes. Set up a new coupon under Coupons tab of the "Appointment Types" page and select "Each code can be used: Total number of uses..." and set it as "1". Then with each purchase on the deal site (Groupon, LivingSocial, etc) you'll create a new code to distribute to each customer under "Enter multiple coupon codes...".
Deal sites like Groupon can sometimes provide users with a list of potential codes that will be generated when a purchase is made. After receiving that potential codes list each code can be added into the "Coupon Codes" area in Acuity, so that clients can immediately use their deal site generated code on your Acuity scheduling page.