The cost of a Manila tour can vary depending on the type of tour and the itinerary. Generally, a walking or bike tour may cost around $20-30 per person, while a more extensive tour with transportation and meals included may cost several hundred dollars per person.
By the way, Manila (especially) and Boracay are significantly more expensive than other parts of The Philippines and once you are out of the tourist hot-spots it's relatively easy to thrive on a budget of $35 a day.