I really think could become a very informative thread for lots of people.
Lets try and do the best we can do to document some useful stuff.
As a start, I found a site that looks interesting. There are a number of cities that can be selected (Just look at the drop down menu at the top). The currency base can also be changed.
Take a look here :-
http://www.numbeo.com/cost-of-living...ry=Philippines