If you need cheap eyeglasses and frames, let us say as low as Php 50, you may want to check a chain of eye wear stores in Sta. Cruz (Back of Quiapo Church). My officemates went there last year and according to them, the street can easily be found because it was just near the LRT Carriedo Station.
They were able to buy eyeglasses for a very very low price. They also bought some fancy eye wears for a very affordable price. They invited to join them since they were planning to eat in a known Chinese resto near the place, but I was not able to join them because it was a Sunday. So they just modeled to me their new eye wears when I report to the office. Hmm… I think I miss my officemates in Manila.