Groupon is a perfectly fine website to find laser deals on. You do, however, have to go to the website for the deal, look into what it is they're offering (what's the name of the laser they use? is it laser or ipl? are the technicians certified? are they overseen by a doctor? etc.), and find out if they have a history of experience. Calling them and asking in-depth questions can help. A person who can answer your questions quickly and with confidence is a very good sign. As a bonus, they will often offer to give you extra incentive if you pay direct, since groupon takes a hefty portion of the money when you sign up through them.
Take into consideration their location (a strong, business oriented location indicates that they earn the money to maintain their establishment), and if absolutely necessary to convince yourself, walk in and take a look around: does it look clean and professional? Do the employees seem used to accommodating people and do they seem knowledgeable?
I can't speak to the efficiency of laser, being in the middle of it myself (with so far amazing results), but I have routinely read over the years that it is extremely effective on light skin, dark hair; that it tends to get the job done in the average 6 sessions (often less, rarely more).
