philippines

I’m flying to the Philippines on Jan 28. Can you help with these questions?
Do you bargain at hotels?
Name of a good bike shop? Availability of 700 x 28c slick tyres, such as Continental. (I live in China – very difficult to get).
Anything worth seeing in or around Manila.
I have never carried a mosquito net, is it necessary & okay to buy in Manila? I either burn coils or use the small electrical ones with the pads.
When taking internal flights, can you cycle up, take off the pedals, turn the handlebars & check in?
Any other useful info appreciated, highlights, classic rides, dangers, etc.
I will need to extend my visa by a week, where can this be done?
Alan