If there ever was a budget spa, Antara Wellness Spa would be it. Despite offering their services at affordable prices, they have a nice place with a comfortable atmosphere. Their best promo is they offer their full body massage at only P300 during off peak hours at 1 to 6 PM. If that doesn't get you to go to their spa in groups, then I don't know what will.
For their couple room, they don't charge extra for couples who want a bit of privacy. Other spas charge a bit extra for private rooms but they don't.
As you can see, their services are extremely affordable. I tried the antara signature massage and it involves bamboo sticks getting whipped at your back among other things. It was one of the most relaxing massages I have ever felt.
They are also located right in the central business district of Makati so if you just experienced a tiring day at work, avail of one of their packages now.