As someone said above, it depends on the demographics of your clients as to whether it's worth offering alcohol to clients.
For me in a rural location, most of them drive so wouldn't partake and my other elderly ladies just don't really drink anymore.
If you are the sort of spa salon / retreat where everyone is there for the day and have lunch with you, then yes, i think it would be worth offering in your spa packages.
P.s.
The most popular tea I serve is PG tips, and the most compliments go to Asda brand gold blend coffee!!