It depends on whether you want furnished or not. Furnished one bedroomed apartments are not that easy to find although they are about, but usually not nice furniture/beds and cheap fridge, cookers and plumbing, all crap.
Don't be worried about looking at the studios, they sometimes are not studios and are a sort of two roomed set up by a stud partition which isn't great but gives an illusion.
The apartment you mention above, furnished and bills inc, guestimate 17-22,000. You won't get unfurnished with bills included.
You could half that if you had your own stuff to move in and were happy to pay the bills.
But you really could pay anything from 4000pesos p/m behind the local colmado, to 45,000pesos p/m by some deluded Italian investor from mars.